Cowpea(Vigna imguicuiata) is an important legume crop with diverse uses. The species is presently a minor crop, and evaluation of its genetic diversity has been very limited. In this study, a total of 200 genic and 10...Cowpea(Vigna imguicuiata) is an important legume crop with diverse uses. The species is presently a minor crop, and evaluation of its genetic diversity has been very limited. In this study, a total of 200 genic and 100 genomic simple sequence repeat(SSR) markers were developed from cowpea unigene and genome sequences, respectively. Among them, 27 genic and 27 genomic SSR markers were polymorphic and were used for assessment of genetic diversity and population structure in 105 selected cowpea accessions. A total of 155 alleles and 2.9 alleles per marker were identified, and the average polymorphic information content(PIC) value was 0.3615. The average PIC of genomic SSRs(0.3996) was higher than that of genic SSRs(0.3235), and most of the polymorphic genomic SSRs were composed of di-and trinucleotide repeats(51.9% and 37.0% of all loci, respectively). The low level of detected genetic diversity may be attributed to a severe genetic bottleneck that occurred during the cowpea domestication process. The accessions were classified by structure and cluster analysis into four subgroups that correlated well with their geographic origins or collection sites. The classification results were also consistent with the results from principal coordinate analysis and can be used as a guide during future germplasm collection and selection of accessions as breeding materials for cultivar improvement. The newly developed genic and genomic SSR markers described in this study will be valuable genomic resources for the assessment of genetic diversity, population structure, evaluation of germplasm accessions, construction of genetic maps, identification of genes of interest,and application of marker-assisted selection in cowpea breeding programs.展开更多
This study is aimed as to evaluate the interaction between salt tolerant Bradyrhizobium sp. and Glomus mosseae in the rhizosphere of legume crop Vigna radiata L. under pot culture and field conditions in different sal...This study is aimed as to evaluate the interaction between salt tolerant Bradyrhizobium sp. and Glomus mosseae in the rhizosphere of legume crop Vigna radiata L. under pot culture and field conditions in different saline zones of West Bengal, India. Bradyrhizobium sp. when inoculated alone showed marked increase in number of nodules, root and shoot length, total plant biomass, arbuscular mycorrhizal fungal (AMF) colonization and population etc. when compared with plants inoculated only with AMF. However, when used in combination, the in oculants showed marked change in the above mentioned parameters over single inoculation of both salt tolerant AM fungi and Bradyrhizobium. These results suggest that AMF along with Bradyrhizobium can greatly help in establishment of V. radiata L. cultivation in the saline soils of West Bengal, India. The increased production of the legume crop could also lead to further benefit of the poor farmers by up lifting their socio-economic conditions with the net profit achieved by cultivating this crop in saline stress condition of West Bengal as a second crop during rabi season.展开更多
Savanna regions of Nigeria are deficient in nitrogen and phosphorus, which retard the growth and yield of crops. Therefore, a study was conducted in the wet season of 2006 at the Dry Land Teaching and Research Farm of...Savanna regions of Nigeria are deficient in nitrogen and phosphorus, which retard the growth and yield of crops. Therefore, a study was conducted in the wet season of 2006 at the Dry Land Teaching and Research Farm of Usmanu Danfodiyo University, Sokoto to evaluate the effect of phosphorus on the growth and yield of two cowpea varieties sourced from Republic of Niger. Treatment consisted of four (4) rates of phosphorus (0, 20, 40, 60 kg.ha–1) factorialy combined with (2) varieties of cowpea (kvx303096G and TN5-78) and laid out in a randomized complete block design (RCBD) replicated three (3) times. Results showed significant response to applied P on pods per plant, grain and stover yield and 100-seed weight with highest response to the application of 60 kg.P.ha–1. From this study it can be concluded that KVX303096G and TN5-78 could both be sown under Sokoto condition to obtain reasonable yield of about 1 t.ha–1 of grain and 1.6 t.ha–1 of stover. Irrespective of the varieties, application of 60 kg P2O5 ha–1 could be recommended for higher yield of cowpea (1.4 t.ha–1) relative to 0 kg.P.ha–1 that yielded 1.0 t.ha–1.展开更多
Cowpea [Vigna unguiculata (L.)] is one of the most important arid legumes cultivated for pulse and forage production. Drought is one of the most damageable constraints to crop production impacting negatively food secu...Cowpea [Vigna unguiculata (L.)] is one of the most important arid legumes cultivated for pulse and forage production. Drought is one of the most damageable constraints to crop production impacting negatively food security. The potential of cowpea to address food security is well established. However, not much is known about the base index selection method in breeding cowpea for drought tolerance, which is important for yields. Consequently, the present study has been conducted to: 1) evaluate the yield performance of cowpea genotypes under artificial drought and well-watered condition, 2) ranke genotype performance using selection indices, and 3) assess relationship between agronomic traits and yield. The experiment was the 2 watering conditions laid out in a Randomized Complete Block Design (RCBD) with three replications. The experiment was carried out in pots under screen house at the Department of Horticulture at KNUST. The result showed that KPR1-96-73, Simbo, CZ06-4-16, Wilibaly and Agyenkwa were high yielding in well-water condition while Ghana Shoba, Sangaraka, Nketewade, Ghana Shoni and Korobalen were high yielding genotypes in water stress condition. The average yield reduction was 60.6% and 16% for grain and fodder yield respectively. The biplot displays revealed four groups among the genotypes tested which were based on their yielding capacity and drought tolerance. In cluster B high yielding and drought tolerant genotypes were identified, high yielding and drought susceptible have been identified in cluster A, low yielding and drought tolerant in cluster D, and lastly low yielding and drought susceptible in cluster C. Genotypes in cluster B were best due to the fact that it combines high yield and tolerance to drought. They were Ghana Shoni, Nketewade, Sangaraka and Ghana Shoba. These genotypes might be suitably employed in further drought tolerance breeding programs of cowpea. Significant relationships were observed between agronomic trait and yields under drought condition.展开更多
Cowpea [(Vigna unguiculata (L.)] is one of the most important arid legumes cultivated for pulse and forage production. However, in cowpea, not much is known about the base index selection method in breeding for drough...Cowpea [(Vigna unguiculata (L.)] is one of the most important arid legumes cultivated for pulse and forage production. However, in cowpea, not much is known about the base index selection method in breeding for drought tolerance. Consequently, the present study has been conducted to: 1) evaluate the yield performance of cowpea genotypes under artificial drought and well-watered condition;2) develop a base index using multiple traits for ranking genotype performance. The experiment was a 25 × 2 factorial laid out in a Randomized Complete Block Design (RCBD) with three replications. The experiment was carried out in the screen house at the Department of Horticulture at KNUST. The result showed that KPR1-96-73, Simbo, CZ06-4-16, Wilibaly and Agyenkwa were high yielding in well-water condition while Ghana Shoba, Sangaraka, NKetewade, Ghana-Shoni and Korobalen were high yielding genotypes in water stress condition. The average yield reduction was 60.6% for grain respectively. The biplot displays revealed four groups among the genotypes tested which was based on their yielding capacity and drought tolerance. In cluster B high yielding and drought tolerant genotypes were identified, high yielding and drought susceptible have been identified in cluster A, low yielding and drought tolerant in cluster D, and lastly low yielding and drought susceptible in cluster C. Genotypes in cluster B, were the best due to the fact that it combines high yield and tolerance to drought. They were Ghana Shoni, Nketewade, Sangaraka and Ghana shoba. These genotypes might be suitably employed in further drought tolerance breeding program of cowpea.展开更多
Vigna unguiculata L. Walp is a recalcitrant plant in terms of in vitro cell, tissue and organ differentiation, which makes it difficult to apply tissue-culture dependant approaches for obtaining stable genetic transfo...Vigna unguiculata L. Walp is a recalcitrant plant in terms of in vitro cell, tissue and organ differentiation, which makes it difficult to apply tissue-culture dependant approaches for obtaining stable genetic transformation in cowpea. Despite this, sporadic efforts have been made to develop regeneration systems in cowpea during the past 40 years. This review presents the considerable progress on cowpea regeneration （organogenesis and embryogenesis） and especially focuses on the regeneration mode of organogenesis, including highlights of the effect of genotypes, explants, medium and plant hormones used in tissue culture. The existing problems and the future research directions were also discussed.展开更多
The objective of this study was to characterize environment factors involved in loss of seed viability during storage in open granaries. The temperature and relative humidity of the granary as well as the equilibrium ...The objective of this study was to characterize environment factors involved in loss of seed viability during storage in open granaries. The temperature and relative humidity of the granary as well as the equilibrium moisture content of seeds were determined monthly. Their effects on the loss of viability of maize (<i>Zea mays</i> L.) and cowpea (<i>Vigna unguiculata</i> (L.) Walp.) seeds were examined. The results showed that relative humidity levels > 65% associated with temperatures > 25°C (conditions in the open granary) do not guarantee safe storage of maize lots for a period of 9 to 12 months. Based on these data and the results of seed viability analysis, local environmental conditions in Gandajika (DR-Congo) and seed genetic background are the main factors for the rapid deterioration of seeds during storage. The germination rate correlated negatively with storage duration (<span style="font-family:;" "="">-0.94) and temperature (-0.57) while it correlates positively with the relative humidity (0.58) for both lots of maize analyzed. The same trend was observed with the two-cowpea varieties studied (IT82D-889 and Diamant). Similar work using more varieties in other granaries is required to validate key factors involved in seed viability during storage in targeted regions.</span>展开更多
Sixteen mungbean lines were analyzed using 56 random primers. Different DNA bands were detected between Bruchid resistant lines and susceptible lines. According to the cluster results, the 16 lines can be divided into...Sixteen mungbean lines were analyzed using 56 random primers. Different DNA bands were detected between Bruchid resistant lines and susceptible lines. According to the cluster results, the 16 lines can be divided into four groups, including brucid resistant wild types, resistant cultivated lines, resistant progenies and a mixed group. BSA method was used to identify DNA markers that related with bruchid resistant gene by using resistant line and susceptible line and their F2 progeny. One codominant marker was identified, which generated a fragment of 1.79 kb in resistant lines and 1.03 kb in susceptible lines. Finally, this codominant marker was considered to be tightly linked with bruchid resistant gene and could be useful in resistant germplasm identification and marker-assisted selection.展开更多
Powdery mildew, which called Sphaerotheca phaseoli in Latin, is one of the major diseases of mungbean （Vigna radiata L.） worldwide, causing up to 50% yield losses. Most mungbean varieties grown in Thailand are susce...Powdery mildew, which called Sphaerotheca phaseoli in Latin, is one of the major diseases of mungbean （Vigna radiata L.） worldwide, causing up to 50% yield losses. Most mungbean varieties grown in Thailand are susceptible to the disease, therefore, new resistant varieties are highly desirable. Three resistant mungbean lines, V4718, V4758 and V4785, were identified from the AVRDC collection. In this study, the authors compared the resistance levels among these 3 lines and tested the allelic relationship among these resistance genes. Three crosses, V4718 × V4758, V4718 × V4785 and V4758 × V4785, were made and the F1 hybrids were selfed to generate the F2 populations and crossed to a susceptible variety, CN72 to generate the F1 × S populations. In the F1 × S and F2 populations, the resistance segregated in a ratio of 3 Resistant （R）：I Susceptible （S） and 15R：IS, respectively for all three crosses. These results indicate that a single dominant gene confers resistance to powdery mildew in each resistant line and these resistance genes are non-allelic. The authors are currently transferring these resistance genes into commercial varieties to provide durable resistance to powdery mildew.展开更多
The study was undertaken to develop and evaluate evapotranspiration model for black gram (Vigna Mungo L.) crop under climatic conditions of Udaipur, India. Pan evaporation data for the duration of twenty three years (...The study was undertaken to develop and evaluate evapotranspiration model for black gram (Vigna Mungo L.) crop under climatic conditions of Udaipur, India. Pan evaporation data for the duration of twenty three years (1978-2001) and measured black gram evapotranspiration data by electronic lysimeter for duration of kharif season of 2001 were used for analysis. Black gram is an important crop of Udaipur region. No sys-tematic study on modelling of black gram evapotranspiration was conducted in past under above said cli-matic conditions. Therefore, stochastic model was developed for the estimation of daily black gram evapotranspiration using 24 years data. Validation of the developed models was done by the comparison of the estimated values with the measured values. The developed stochastic model for black gram evapotran-spiration was found to predict the daily black gram evapotranspiration very accurately.展开更多
Phosphate fertilizers when applied to the soil, besides being harvested by the crops, promote a residual effect that can be offered to subsequent crops. The objective of this research was to evaluate the residual effe...Phosphate fertilizers when applied to the soil, besides being harvested by the crops, promote a residual effect that can be offered to subsequent crops. The objective of this research was to evaluate the residual effect of phosphate fertilization applied to maize cultivation on the successor crop, cowpea, in the Cerrado region in Maranhao. The research was carried out in the experimental area of Federal University of Maranhao (UFMA), located in the city of Chapadinha, MA (3°44'30"S, 43°21'37''W). The experimental design was in randomized blocks, with six treatments and four replications. The treatments were composed of the following residual P doses: 0, 60, 70, 80, 90, 100 kg·ha-1 of P2O5. The cultivation of cowpea (cultivar BRS guariba) was sown at a spacing of 1.0 × 0.20 m. The cowpea proved to be efficient in the use of residual phosphate fertilization, since it promoted grain yield close to the national average. The cultivation of cowpea in previously cultivated areas is feasible, in order to take advantage of the residual phosphate fertilization in the Cerrado of East of Maranhao. The phosphorus dose applied in the predecessor crop corresponding to 80 kg·ha-1 of P2O5 promoted higher grain yield (393.44 Mg·ha-1) and a greater profit margin (US $326.26). Thus, it is feasible to grow cowpea in previously cultivated areas, in order to take advantage of residual phosphate fertilization.展开更多
Cowpea, string Bean, or Macassar bean [Vigna unguiculata (L.) Walp] presents a short life cycle, low water requirement, develops in soils of low fertility, and has the ability to fix nitrogen from the air. In the Cerr...Cowpea, string Bean, or Macassar bean [Vigna unguiculata (L.) Walp] presents a short life cycle, low water requirement, develops in soils of low fertility, and has the ability to fix nitrogen from the air. In the Cerrado, the oxisols occupy practically all the flat to soft-wavy areas with little reserve of nutrients for the plants, in general, they are soils with great limitations of fertility. A source of alternative phosphate fertilization is the use of reactive natural phosphates. The reactive natural phosphate of Bayóvar presents intermediate solubility between the sources of soluble phosphates and the natural phosphates. In this context, the objective was to evaluate the initial development of Cowpea beans fertilized with the natural Bayóvar phosphate used for cultivation of the Brazilian Cerrado Oxisol. The experimental design was completely randomized, with six doses of phosphorus (0, 100, 200, 300, 400, 500 mg·dm-3) using natural Bayovar phosphate as a source in four replications. The species used in this study was the legume cowpea bean [Vigna unguiculata (L.) Walp] cultivar Tumucumaque. The treatments were applied using the natural phosphate Bayóvar as a source of phosphorus (29% of P2O5). At 33 DAS (days after sowing), the variable number of leaves of the Cowpea bean was analyzed and at 40 DAS, the variables plant height, SPAD chlorophyll index (Soil Plant Analysis Development) and stem diameter were analyzed. For all variables analyzed there was a significant effect. The initial development of the cowpea bean cultivated in the Brazilian Cerrado Oxisol was significantly influenced by the Bayóvar natural phosphate fertilization with the best phosphorus (P2O5) doses in the range of 200 to 350 mg·展开更多
基金funded by the Agricultural Science and Technology Innovation Program (ASTIP) of CAASthe China Agriculture Research System (CARS-09)
文摘Cowpea(Vigna imguicuiata) is an important legume crop with diverse uses. The species is presently a minor crop, and evaluation of its genetic diversity has been very limited. In this study, a total of 200 genic and 100 genomic simple sequence repeat(SSR) markers were developed from cowpea unigene and genome sequences, respectively. Among them, 27 genic and 27 genomic SSR markers were polymorphic and were used for assessment of genetic diversity and population structure in 105 selected cowpea accessions. A total of 155 alleles and 2.9 alleles per marker were identified, and the average polymorphic information content(PIC) value was 0.3615. The average PIC of genomic SSRs(0.3996) was higher than that of genic SSRs(0.3235), and most of the polymorphic genomic SSRs were composed of di-and trinucleotide repeats(51.9% and 37.0% of all loci, respectively). The low level of detected genetic diversity may be attributed to a severe genetic bottleneck that occurred during the cowpea domestication process. The accessions were classified by structure and cluster analysis into four subgroups that correlated well with their geographic origins or collection sites. The classification results were also consistent with the results from principal coordinate analysis and can be used as a guide during future germplasm collection and selection of accessions as breeding materials for cultivar improvement. The newly developed genic and genomic SSR markers described in this study will be valuable genomic resources for the assessment of genetic diversity, population structure, evaluation of germplasm accessions, construction of genetic maps, identification of genes of interest,and application of marker-assisted selection in cowpea breeding programs.
文摘This study is aimed as to evaluate the interaction between salt tolerant Bradyrhizobium sp. and Glomus mosseae in the rhizosphere of legume crop Vigna radiata L. under pot culture and field conditions in different saline zones of West Bengal, India. Bradyrhizobium sp. when inoculated alone showed marked increase in number of nodules, root and shoot length, total plant biomass, arbuscular mycorrhizal fungal (AMF) colonization and population etc. when compared with plants inoculated only with AMF. However, when used in combination, the in oculants showed marked change in the above mentioned parameters over single inoculation of both salt tolerant AM fungi and Bradyrhizobium. These results suggest that AMF along with Bradyrhizobium can greatly help in establishment of V. radiata L. cultivation in the saline soils of West Bengal, India. The increased production of the legume crop could also lead to further benefit of the poor farmers by up lifting their socio-economic conditions with the net profit achieved by cultivating this crop in saline stress condition of West Bengal as a second crop during rabi season.
文摘Savanna regions of Nigeria are deficient in nitrogen and phosphorus, which retard the growth and yield of crops. Therefore, a study was conducted in the wet season of 2006 at the Dry Land Teaching and Research Farm of Usmanu Danfodiyo University, Sokoto to evaluate the effect of phosphorus on the growth and yield of two cowpea varieties sourced from Republic of Niger. Treatment consisted of four (4) rates of phosphorus (0, 20, 40, 60 kg.ha–1) factorialy combined with (2) varieties of cowpea (kvx303096G and TN5-78) and laid out in a randomized complete block design (RCBD) replicated three (3) times. Results showed significant response to applied P on pods per plant, grain and stover yield and 100-seed weight with highest response to the application of 60 kg.P.ha–1. From this study it can be concluded that KVX303096G and TN5-78 could both be sown under Sokoto condition to obtain reasonable yield of about 1 t.ha–1 of grain and 1.6 t.ha–1 of stover. Irrespective of the varieties, application of 60 kg P2O5 ha–1 could be recommended for higher yield of cowpea (1.4 t.ha–1) relative to 0 kg.P.ha–1 that yielded 1.0 t.ha–1.
文摘Cowpea [Vigna unguiculata (L.)] is one of the most important arid legumes cultivated for pulse and forage production. Drought is one of the most damageable constraints to crop production impacting negatively food security. The potential of cowpea to address food security is well established. However, not much is known about the base index selection method in breeding cowpea for drought tolerance, which is important for yields. Consequently, the present study has been conducted to: 1) evaluate the yield performance of cowpea genotypes under artificial drought and well-watered condition, 2) ranke genotype performance using selection indices, and 3) assess relationship between agronomic traits and yield. The experiment was the 2 watering conditions laid out in a Randomized Complete Block Design (RCBD) with three replications. The experiment was carried out in pots under screen house at the Department of Horticulture at KNUST. The result showed that KPR1-96-73, Simbo, CZ06-4-16, Wilibaly and Agyenkwa were high yielding in well-water condition while Ghana Shoba, Sangaraka, Nketewade, Ghana Shoni and Korobalen were high yielding genotypes in water stress condition. The average yield reduction was 60.6% and 16% for grain and fodder yield respectively. The biplot displays revealed four groups among the genotypes tested which were based on their yielding capacity and drought tolerance. In cluster B high yielding and drought tolerant genotypes were identified, high yielding and drought susceptible have been identified in cluster A, low yielding and drought tolerant in cluster D, and lastly low yielding and drought susceptible in cluster C. Genotypes in cluster B were best due to the fact that it combines high yield and tolerance to drought. They were Ghana Shoni, Nketewade, Sangaraka and Ghana Shoba. These genotypes might be suitably employed in further drought tolerance breeding programs of cowpea. Significant relationships were observed between agronomic trait and yields under drought condition.
文摘Cowpea [(Vigna unguiculata (L.)] is one of the most important arid legumes cultivated for pulse and forage production. However, in cowpea, not much is known about the base index selection method in breeding for drought tolerance. Consequently, the present study has been conducted to: 1) evaluate the yield performance of cowpea genotypes under artificial drought and well-watered condition;2) develop a base index using multiple traits for ranking genotype performance. The experiment was a 25 × 2 factorial laid out in a Randomized Complete Block Design (RCBD) with three replications. The experiment was carried out in the screen house at the Department of Horticulture at KNUST. The result showed that KPR1-96-73, Simbo, CZ06-4-16, Wilibaly and Agyenkwa were high yielding in well-water condition while Ghana Shoba, Sangaraka, NKetewade, Ghana-Shoni and Korobalen were high yielding genotypes in water stress condition. The average yield reduction was 60.6% for grain respectively. The biplot displays revealed four groups among the genotypes tested which was based on their yielding capacity and drought tolerance. In cluster B high yielding and drought tolerant genotypes were identified, high yielding and drought susceptible have been identified in cluster A, low yielding and drought tolerant in cluster D, and lastly low yielding and drought susceptible in cluster C. Genotypes in cluster B, were the best due to the fact that it combines high yield and tolerance to drought. They were Ghana Shoni, Nketewade, Sangaraka and Ghana shoba. These genotypes might be suitably employed in further drought tolerance breeding program of cowpea.
文摘Vigna unguiculata L. Walp is a recalcitrant plant in terms of in vitro cell, tissue and organ differentiation, which makes it difficult to apply tissue-culture dependant approaches for obtaining stable genetic transformation in cowpea. Despite this, sporadic efforts have been made to develop regeneration systems in cowpea during the past 40 years. This review presents the considerable progress on cowpea regeneration （organogenesis and embryogenesis） and especially focuses on the regeneration mode of organogenesis, including highlights of the effect of genotypes, explants, medium and plant hormones used in tissue culture. The existing problems and the future research directions were also discussed.
文摘The objective of this study was to characterize environment factors involved in loss of seed viability during storage in open granaries. The temperature and relative humidity of the granary as well as the equilibrium moisture content of seeds were determined monthly. Their effects on the loss of viability of maize (<i>Zea mays</i> L.) and cowpea (<i>Vigna unguiculata</i> (L.) Walp.) seeds were examined. The results showed that relative humidity levels > 65% associated with temperatures > 25°C (conditions in the open granary) do not guarantee safe storage of maize lots for a period of 9 to 12 months. Based on these data and the results of seed viability analysis, local environmental conditions in Gandajika (DR-Congo) and seed genetic background are the main factors for the rapid deterioration of seeds during storage. The germination rate correlated negatively with storage duration (<span style="font-family:;" "="">-0.94) and temperature (-0.57) while it correlates positively with the relative humidity (0.58) for both lots of maize analyzed. The same trend was observed with the two-cowpea varieties studied (IT82D-889 and Diamant). Similar work using more varieties in other granaries is required to validate key factors involved in seed viability during storage in targeted regions.</span>
基金the National Natural Science Foundation of China(30170635).
文摘Sixteen mungbean lines were analyzed using 56 random primers. Different DNA bands were detected between Bruchid resistant lines and susceptible lines. According to the cluster results, the 16 lines can be divided into four groups, including brucid resistant wild types, resistant cultivated lines, resistant progenies and a mixed group. BSA method was used to identify DNA markers that related with bruchid resistant gene by using resistant line and susceptible line and their F2 progeny. One codominant marker was identified, which generated a fragment of 1.79 kb in resistant lines and 1.03 kb in susceptible lines. Finally, this codominant marker was considered to be tightly linked with bruchid resistant gene and could be useful in resistant germplasm identification and marker-assisted selection.
文摘Powdery mildew, which called Sphaerotheca phaseoli in Latin, is one of the major diseases of mungbean （Vigna radiata L.） worldwide, causing up to 50% yield losses. Most mungbean varieties grown in Thailand are susceptible to the disease, therefore, new resistant varieties are highly desirable. Three resistant mungbean lines, V4718, V4758 and V4785, were identified from the AVRDC collection. In this study, the authors compared the resistance levels among these 3 lines and tested the allelic relationship among these resistance genes. Three crosses, V4718 × V4758, V4718 × V4785 and V4758 × V4785, were made and the F1 hybrids were selfed to generate the F2 populations and crossed to a susceptible variety, CN72 to generate the F1 × S populations. In the F1 × S and F2 populations, the resistance segregated in a ratio of 3 Resistant （R）：I Susceptible （S） and 15R：IS, respectively for all three crosses. These results indicate that a single dominant gene confers resistance to powdery mildew in each resistant line and these resistance genes are non-allelic. The authors are currently transferring these resistance genes into commercial varieties to provide durable resistance to powdery mildew.
文摘The study was undertaken to develop and evaluate evapotranspiration model for black gram (Vigna Mungo L.) crop under climatic conditions of Udaipur, India. Pan evaporation data for the duration of twenty three years (1978-2001) and measured black gram evapotranspiration data by electronic lysimeter for duration of kharif season of 2001 were used for analysis. Black gram is an important crop of Udaipur region. No sys-tematic study on modelling of black gram evapotranspiration was conducted in past under above said cli-matic conditions. Therefore, stochastic model was developed for the estimation of daily black gram evapotranspiration using 24 years data. Validation of the developed models was done by the comparison of the estimated values with the measured values. The developed stochastic model for black gram evapotran-spiration was found to predict the daily black gram evapotranspiration very accurately.
文摘Phosphate fertilizers when applied to the soil, besides being harvested by the crops, promote a residual effect that can be offered to subsequent crops. The objective of this research was to evaluate the residual effect of phosphate fertilization applied to maize cultivation on the successor crop, cowpea, in the Cerrado region in Maranhao. The research was carried out in the experimental area of Federal University of Maranhao (UFMA), located in the city of Chapadinha, MA (3°44'30"S, 43°21'37''W). The experimental design was in randomized blocks, with six treatments and four replications. The treatments were composed of the following residual P doses: 0, 60, 70, 80, 90, 100 kg·ha-1 of P2O5. The cultivation of cowpea (cultivar BRS guariba) was sown at a spacing of 1.0 × 0.20 m. The cowpea proved to be efficient in the use of residual phosphate fertilization, since it promoted grain yield close to the national average. The cultivation of cowpea in previously cultivated areas is feasible, in order to take advantage of the residual phosphate fertilization in the Cerrado of East of Maranhao. The phosphorus dose applied in the predecessor crop corresponding to 80 kg·ha-1 of P2O5 promoted higher grain yield (393.44 Mg·ha-1) and a greater profit margin (US $326.26). Thus, it is feasible to grow cowpea in previously cultivated areas, in order to take advantage of residual phosphate fertilization.
文摘Cowpea, string Bean, or Macassar bean [Vigna unguiculata (L.) Walp] presents a short life cycle, low water requirement, develops in soils of low fertility, and has the ability to fix nitrogen from the air. In the Cerrado, the oxisols occupy practically all the flat to soft-wavy areas with little reserve of nutrients for the plants, in general, they are soils with great limitations of fertility. A source of alternative phosphate fertilization is the use of reactive natural phosphates. The reactive natural phosphate of Bayóvar presents intermediate solubility between the sources of soluble phosphates and the natural phosphates. In this context, the objective was to evaluate the initial development of Cowpea beans fertilized with the natural Bayóvar phosphate used for cultivation of the Brazilian Cerrado Oxisol. The experimental design was completely randomized, with six doses of phosphorus (0, 100, 200, 300, 400, 500 mg·dm-3) using natural Bayovar phosphate as a source in four replications. The species used in this study was the legume cowpea bean [Vigna unguiculata (L.) Walp] cultivar Tumucumaque. The treatments were applied using the natural phosphate Bayóvar as a source of phosphorus (29% of P2O5). At 33 DAS (days after sowing), the variable number of leaves of the Cowpea bean was analyzed and at 40 DAS, the variables plant height, SPAD chlorophyll index (Soil Plant Analysis Development) and stem diameter were analyzed. For all variables analyzed there was a significant effect. The initial development of the cowpea bean cultivated in the Brazilian Cerrado Oxisol was significantly influenced by the Bayóvar natural phosphate fertilization with the best phosphorus (P2O5) doses in the range of 200 to 350 mg·
