Screen House Assessment of Cowpea [(Vigna unguiculata (L.)] Genotypes for Drought Tolerance Using Selection Indices

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.

Selection of Cowpea [(Vigna unguiculata (L.) WALP] Genotypes for Drought Tolerance Using Selection Indices

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.

Genetic diversity and a population structure analysis of accessions in the Chinese cowpea [Vigna unguiculata(L.)Walp.]germplasm collection

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.

Influence of phosphorus on the performance of cowpea (Vigna unguiculata (L) Walp.) varieties in the Sudan savanna of Nigeria

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.

A Review on Regeneration in Cowpea （Vigna unguiculata L. Walp）

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.

Loss of Certified Maize (<i>Zea mays</i>L.) and Cowpea (<i>Vigna unguiculata</i>(L.) Walp.) Seed Viability during Storage in a Sub-Saharan Region: Analysis of Environmental Factors

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 (Zea mays L.) and cowpea (Vigna unguiculata (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 (-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.

羊肚菌-豇豆轮作高效栽培模式及效益分析

羊肚菌属低温型真菌,一般在11月下旬至12月初栽培,翌年4月前收获。豇豆种植业为一项短平快的发展项目,可有效提升种植户的经济收入水平。羊肚菌与豇豆进行轮作栽培,能充分利用设施条件,且可有效降低作物连作障碍,提高效益。文章总结了适宜河南省设施羊肚菌与豇豆周年循环轮作栽培模式的高效栽培技术,并对该模式进行了效益分析。该模式每667 m^(2)羊肚菌产量约500 kg,豇豆产量约2000 kg,按照近3年均价计算,每667 m^(2)产值达4.5万元,投入生产成本共计1.591万元,利润可达2.909万元。

外源NO对豇豆采后贮藏品质的影响

目的探究一氧化氮(NO)对豇豆采后贮藏品质的影响。方法以硝普钠(sodium nitroprusside,SNP)为外源NO供体,采用0.3 mmol/L的SNP溶液浸泡处理豇豆10 min(以蒸馏水浸泡为对照),测定15℃贮藏条件下豇豆贮藏品质和生理特性的变化。结果SNP处理能很好地保持豇豆的感官品质,有效保持其水分,同时保持了豇豆营养物质(维生素C、可溶性固形物、叶绿素)的含量。此外,显著降低了乙烯释放量(P<0.05),较好地保持了硬度,抑制了丙二醛含量的升高,还降低了纤维素酶和多聚半乳糖醛酸酶的活性,因此有效维持了细胞壁的完整性;提高了抗氧化物质(总酚、类黄酮)的含量、抗氧化酶(抗坏血酸过氧化物酶、过氧化氢酶)的活性(P<0.05),并显著抑制了褐变相关指标(过氧化物酶、多酚氧化酶)的活性(P<0.05)。结论外源NO处理可以延长豇豆的采后贮藏期并保持其贮藏品质。

Planting Adaptability of Four Kinds of Common Vegetabless in Shanghai

[Objectives]To explore the planting adaptability of vegetables in Shanghai.[Methods]In this paper,cowpea(Vigna unguiculate(L.)Walp.),cucumber(Cucumis sativus L.),eggplant(Solanum melongena L.)and potato(Solanum tuberosum L.)were selected as experimental materials and planted in the open air.The growth status,the occurrence of diseases and insect pests,and the taste evaluation of these four kinds of common vegetables were mainly studied.[Results]The results showed that the four kinds of common vegetables in Shanghai had strong growth,strong adaptability,less pests and diseases,and good taste.[Conclusions]The cowpea,cucumber,eggplant,and potato are suitable for planting in Shanghai.

海南豇豆多菌灵、啶虫脒和阿维菌素残留及其膳食风险评估

【目的】探明海南产区豇豆中多菌灵、啶虫脒和阿维菌素的残留水平及膳食暴露风险情况,为豇豆风险监管提供科学依据。【方法】应用超高效液相色谱—串联质谱法对采自海南省的295份豇豆样品中多菌灵、啶虫脒和阿维菌素残留进行检测,通过风险商(HI)对3种农药残留膳食风险进行评估。【结果】295份豇豆样品中有242份(82.0%)样品农药残留为阳性,多菌灵、啶虫脒和阿维菌素在样品中的检出率分别为45.8%、64.4%和28.8%,残留值范围分别为0.016~3.049、0.015~1.710和0.011~0.312 mg/kg。通过食用豇豆摄入多菌灵、啶虫脒和阿维菌素残留的最高HI分别为0.200、0.262和0.718。【结论】海南产区豇豆中多菌灵、啶虫脒和阿维菌素的膳食暴露风险在可接受水平,不会给公众健康带来危害。

不同浓度NaCl胁迫处理下豇豆幼苗抗氧化酶活性的变化

本研究主要探讨不同浓度NaCl胁迫处理下豇豆(Vigna unguiculata Linn.)幼苗叶片抗氧化酶活性的变化情况。研究结果表明,在0～250mmol/L NaCl胁迫下,随着盐浓度的增加,豇豆幼苗叶片可溶性蛋白质、脯氨酸和丙二醛含量逐渐增加,在150mmol/L浓度时,3者的含量都达到最大值;而超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)的活性开始逐渐上升,它们的活性分别在100mmol/L、150mmol/L和150mmol/L时达到最大值,然后逐渐下降。同时,对NaCl胁迫下3种抗氧化酶基因的表达进行适时定量PCR分析,分析结果显示3种抗氧化酶基因的转录表达与酶活性的变化一致。说明在不同浓度的NaCl胁迫下,NaCl诱导了sod、pod和cat3种抗氧化酶基因的表达,3种抗氧化酶活性相应地提高,从而提高了豇豆应对NaCl胁迫的能力。本文结果将为今后豇豆在盐碱栽培生产提供一定的参考。

豇豆产量性状与SSR分子标记的关联分析

利用156对多态性豇豆[Vigna unguiculata（L.）Walp.]简单重复序列（Simple sequence repeat,SSR）引物检测83份豇豆种质材料基因组,分析群体遗传结构,并对14个豇豆产量性状与SSR标记进行全基因组关联分析。结果表明,群体遗传结构分析将83份豇豆样品划分为2个亚群。关联分析则有10个SSR标记位点与8个性状关联,主要分布在LG2、LG3、LG4、LG7、LG11连锁群上。这些关联位点在豇豆基因组上分布不均,对关联性状的表型变异解释率为9%（CLM0022）~33%（CLM0347）;有1个标记（CLM0251）与多个性状关联;另外也有同一个性状与多个SSR标记关联,包括叶宽（CLM0251、CLM0850）,单荚重（CLM0347、CLM0251、CLM0614）。这些与豇豆性状关联的SSR标记将为豇豆分子育种和遗传改良提供依据。

铝胁迫对豇豆幼苗根尖抗氧化系统的影响

选用豇豆铝敏感品种‘S3’和耐铝品种‘T6’为试验材料,研究不同耐铝性豇豆根系伸长和根尖活性氧代谢变化的差异,探讨铝胁迫下不同耐铝性豇豆在活性氧代谢上的差异及其与豇豆耐铝性的关系。结果表明:(1)随着铝处理浓度的增加,2个品种根系伸长均受到抑制,且‘S3’受到的抑制程度大于‘T6’。(2)随着处理铝浓度的升高,2个豇豆品种的根尖O2.-产生速率、H2O2含量、MDA含量及质膜透性都显著增加,且‘S3’的增加幅度大于‘T6’。(3)铝胁迫处理下,2个豇豆品种幼苗根尖超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)活性都有所上升,其中铝敏感品种‘S3’的SOD活性上升幅度比耐铝品种‘T6’高,而POD、CAT、APX的上升幅度比耐铝品种‘T6’低。研究认为,铝胁迫下铝敏感品种‘S3’内活性氧物质过量积累而导致氧化胁迫,使细胞的脂质过氧化程度加剧,最终严重影响根系的生长。

冷藏条件下四种农药在豇豆中的消解动态

研究冷藏条件下高效氯氰菊酯、苯醚甲环唑、乐果和乙酰甲胺磷4种农药在豇豆[Vigna unguiculata（Linn）Walp.]中的消解残留规律。模拟豇豆4-6℃的冷藏储运条件,分别在冷藏后0-5 d采集豇豆样品,采用气相色谱法测定4种农药的残留量。结果表明,4种农药在冷藏条件下降解缓慢,4种农药的消解半衰期均大于10 d,其残留量在冷藏2 d时均消解20%以上,但在2 d后残留量趋于稳定。在豇豆生产中应当严格控制4种农药的施药浓度和施药次数,以保证豇豆的质量安全。

豇豆种子萌发过程中多胺氧化酶活性的变化及其影响因素

吸胀而未萌发的豇豆 (VignaunguiculataL .)种子检测不到多胺氧化酶 (PAO)活性 ,直至萌发开始 (吸胀后 36h)才在胚芽、子叶和胚轴测到PAO活性 ,此后各部分的PAO活性以不同速度增加 ,而胚根一直没能检测到PAO活性。蛋白质合成抑制剂环己酰亚胺 (CHM)吸胀处理可显著抑制萌发种子胚芽和子叶的PAO活性 ,同时强烈抑制种子的萌发 ;核酸合成抑制剂放线菌素D处理对豇豆胚芽和子叶的PAO活性以及种子萌发的影响则远不及CHM处理。豇豆种子在黑暗条件下萌发 ,胚芽和子叶的PAO活性都明显高于光下。适宜浓度的腐胺和CuCl2 吸胀处理也可提高胚芽和子叶的PAO活性。

长豇豆荚色、籽粒色及生长习性的遗传研究

以性状多样的长豇豆为材料 ,对其荚色、籽粒色和生长习性进行遗传分析。结果表明 :籽粒色的相对性状间均表现 1对等位基因差异的遗传 ,黑籽对红籽为显性 ,黑籽对白籽、红籽对白籽均为显性 ,花斑籽对红籽为显性。生长习性由 2对等位基因控制 ,其中蔓生对矮生为显性上位性。荚色因材料不同有的表现为质量性状 ,且紫荚对浅绿荚为显性、浅绿荚对绿荚为显性、白荚对浅绿荚为显性 ;有的表现为数量性状 ,即由多基因控制。

外源水杨酸处理对采后豇豆抗冷性的影响

试验研究了不同浓度的外源水杨酸溶液处理对采后豇豆冷藏效果的影响。结果表明,采用水杨酸处理可以有效地抑制豇豆表面水浸状凹陷斑扩大,改善豇豆冷藏期间的贮藏品质,延缓豇豆豆荚中叶绿素的降解,抑制细胞膜透性的增加和丙二醛含量的积累,并使过氧化物酶和过氧化氢酶活性始终维持在较高水平。其中以1.0mmol/L浓度的水杨酸溶液处理的效果最佳。

豇豆钙调蛋白cDNA的克隆及序列分析

从豇豆成熟叶片中提取总RNA,反转录合成cDNA第一链,根据钙调蛋白结构基因两端保守序列设计引物,PCR扩增豇豆钙调蛋白基因,克隆到T-easy载体上并测定了其全序列.序列分析结果表明,豇豆钙调蛋白基因由450个核苷酸组成,编码150个氨基酸.与已知的多种植物钙调蛋白基因相比有很高的相似性,核苷酸序列相似性在80%以上,编码的氨基酸序列相似性在90%以上.

水杨酸对盐胁迫下豇豆幼苗生长发育的影响

在300mmol／LNaGl胁迫条件下，研究了水杨酸对豇豆[Vigna unguiculata（L．）Walp]幼苗生长发育的影响。结果表明，经水杨酸处理的豇豆幼苗株高、茎粗明显提高，促进了幼苗的形态构建。并且幼苗的超氧化物歧化酶和过氧化物酶活性均显著高于对照，丙二醛含量和电解质渗透率显著或明显降低；水杨酸在适宜的施用浓度范围内能够缓解豇豆幼苗的盐害症状，提高抗盐能力。对豇豆幼苗的生长有一定的促进作用，当水杨酸的处理浓度为100～150mg／L时，作用效果最明显。

豇豆愈伤组织诱导的初步研究

研究了不同浓度的生长素(NAA、2,4-D)和细胞分裂素(6-BA、KT)对豇豆[Vigna unguiculata(Linn.)Walp.]花荣下胚轴和子叶愈伤组织诱导的影响。结果表明,子叶较下胚轴更容易诱导出愈伤组织;子叶切片在MS+3.0 mg/L 2,4-D+0.5 mg/L KT中愈伤诱导率最高,为95.83%,下胚轴茎段在MS+3.0 mg/L2,4-D+0.1 mg/L 6-BA中愈伤诱导率最高,为88.89%。此外,2,4-D与KT组合可诱导子叶产生胚状体。