种植密度对棉花‘新陆早74号’的产量、性状及其品质的影响分析

为了研究不同种植密度下‘新陆早74号’棉花的农艺性状、产量构成及棉纤维品质的变化规律,寻求‘新陆早74号’的最佳种植密度,特设计四种密度试验(18.0、21.0、24.0、27.0 万株/hm2)对其的影响。结果表明:高密度处理下,‘新陆早74号’生育期延长,单株主茎果枝数、结铃数越少,铃重越轻;低密度处理的棉花早熟性好,单株结铃数多,单铃重高;当密度适宜时籽棉和皮棉产量最高;低密度与高密度处理间棉花的衣分率无明显变化;不同密度对棉花纤维长度影响较小,但高密度栽培时棉花断裂比强度下降,马克隆值变小。

Analysis of Yield and Disease Resistance Traits of New Winter Rapeseed Varieties over the Past Twenty Years in China

Based on the results of the national regional trail for winter rapeseed in four groups,including the upper reaches,middle reaches and lower reaches of Yangtze River and Huang-Huai region in the past twenty years,new varieties of winter rapeseed showed upward trend in average yield,the yield level in Huang-huai group was higher than other groups.The changes of average effective pods per plant were not significant in any group,but the number of grain per pod and 1 000-grain weight showed increase trend.However,the increment of grains per pod in three Yangtze River groups was higher than that in Huang-Huai River group,while the increment of 1 000-grain weight was just opposite.The incidence rate of Sclerotinia sclerotiorum and viral disease in new varieties of winter rapeseed obviously decreased,and the incidence rate of S.sclerotiorum decreased lower than 5%.Genetic improvement for winter rapeseed should be focus on the number of grain per pod and 1 000-grain weight in the future,and yield level of new varieties in all four groups is expected to increase.

Correlation Analysis of SPAD Value with Chlorophyll Content and Economic Yield Traits of Brassica napus L.

[Objective] The aim was to compare differences of SPAD value, chloro- phyll content, agronomic characters, economic characters and yield traits to analyze correlation of SPAD value with other indices and establish regression functions. [Method] Based on 34 Brassica napus L. varieties, SPAD value, chlorophyll content, agronomic characters, economic characters and yield traits were measured and re- gression functions were established according to correlations. [Result] SPAD value, chlorophyll content, agronomic and economic characters and yield traits all achieved significant level in differences among 34 varieties. Specifically, SPAD value was of extremely significant correlation with chlorophyll a and b, total chlorophyll and carotenoid, and the correlation from high to low was chl-b〉chl-z〉chl-a〉chl-x. SPAD value was of significantly positive correlation with total pod number per plant, plant height, seed number per pod, yield per plant and harvest yield, and of insignificant correlation with branch point height, effective branch number, pod density of main stem, and pod length. [Conclusion] It is simple and rapid to predict chlorophyll con- tent, economic characters and yields of Brassica napus L. with SPAD value and re- gression functions.

Analysis of Correlation between Yield and Quality Traits of Quality Hybrid Rapeseed

[Objective] This study aimed to investigate the correlation between yield and quality traits of rape. [Method] Taking ＂Sanbei 98＂ and ＂Youyan 599＂ as ex- periment materials, correlation between yield and quality traits of Brassica napus L. cultivars was explored by orthogonal rotation method. [Result] The results showed that： 1 In both the two varieties-Sanbei98 and Youyan599, erucic acid content had the largest coefficient of variation, but its average content was lower than 2% in both the two varieties （0.90% in Sanbei98 and 1.24% in Youyan599）, and the palmitic acid content had the smallest coefficient of variation. 2 In terms of the dif- ferences in quality traits at different yield levels, only the mean of eicosenoic acid content revealed significant difference in Sanbei98, and only the mean of seed-pro- tein content revealed significant difference in Youyan599, and there was no signifi- cant difference in any combined quality traits in both the two varieties. 3 The yield was negatively correlated with the erucic acid content or oil content, and posi- tively correlated with the content of seed-protein, linoleic acid, or linolenic acid, and the coefficient of correlation between the yield and either of the contents of glucosi- nolates, oleic acid, palmitic acid, stearic acid, and eicosenoic acid was smaller. ~, when the yield of a variety increased considerably, there was a certain decreasing trend in erucic acid content, oil content, the total amount of erucic chain fatty acids （El ＆ Er）, while there was an increasing trend in seed-protein content, linoleic acid content, linolenic acid content, saturated fatty acids （SFA）, the total amount of fat and protein （P ＆ F）, unsaturation index （IUFA）, unsaturated fatty acids （UFA）, the total amount of 18 carbon fatty acids （18-C FA）, unsaturated fatty acids [UFA/（Ei ＆ Er） ], and the sum of oleic acid and linoleic acid （OI ＆ Li）. 5 When the seed-pro- tein content is increased, the quality of rape oil cake is also improved; when the unsaturated index is increased, the oil stability is decreased. The increase in the total amount of unsaturated fatty acids, oleic acid and linoleic acid helps to increase in the total amount of fatty acids absorbed by human bodies. [Conclusion] This study provides a theoretical foundation for the cultivation of high-yielding and top- quality hybrid rape cultivars.

Relationship between Grain Yield and Yield Components of Various Rice Cultivars

[Objective] The relationship between grain yield and yield components was investigated in .different rice cultivars at the target yield of 10.5-11.25 t/hm2, to provide theoretical basis for cultivation of high-yield rice. [Method] The yield performance of various super rice and non-super rice cultivars that were cultivated in large area in Sichuan Chengdu was studied under high-yielding cultivation conditions from 2006 to 2008. [Result] The rice yield was closely correlated with the productive panicle number, grain number per panicle, seed setting rate and 1 000-grain weight. The four yield components showed different influences on the yield of different rice culti- vars. By adopting the high yielding cultivation technology （that the seedlings were planted in a triangle shape） at the target yield of 10.5-11.25 t/hm~, we found that the rice yield of super rice cultivars was closely correlated with productive panicle number and 1 000-grain weight, negatively correlated with grain number per panicle, and significantly negatively correlated with seed setting rate; the grain yield of non- super rice cultivars was negatively correlated with grain number per panicle and seed setting rate, and significantly negatively correlated with the productive panicle number and 1 000-grain weight. [Conclusion] The results revealed the relationship between grain yield and yield components in different rice cultivars, which provided references for developing reasonable cultivation measures and thus to improve the yield of super rice in large acreage.

Relation Analysis of Several Agronomic Traits and Single Plant Lint Yield in Upland Cotton with High Quality

[ Objective] The purpose was to study the correlation between main agronomic traits and single plant lint yield in upland cotton with high quality. [ Method] Twenty-four upland cotton lines with high quality were analyzed for single plant lint yield and 10 agronomic traits in a randomized, complete block at the agriculture experimental station of JXAU, Nanchang, China in 2007. They were divided into three types （ high, medium, low yield） based on single plant lint yield by Ward＇s method. A total of 11 traits of three types were compared. Correlation a- nalysis and stepwise regression analysis of 10 agronomic traits to single plant lint yield were carried out. [ Result] There existed statistically sig- nificant difference in bolls per plant, ~int percentage, lint index, fruit node numbers, growth period for three yield types. The high yield type ex- hibited the highest bolls per plant, lint percentage and lint index, the lowest fruit node numbers and the shortest growth period. Bolls per plant, boll weight and single plant lint yield were significantly and positively correlated. Fruit node numbers and single plant lint yield were significantly and negatively correlated. Bolls per plant, boll weight, and fruiting position number were the most important factors influencing single plant lint yield of upland cotton lines with high quality. [ Conclusion ] The results will have certain significance for the development of upland cotton variety with high quality.

Identification of Quantitative Trait Loci for Anthesis-Silking Interval and Yield Components Under Drought Stress in Maize

A genetic linkage map with 89 SSR marker loci was constructed based on a maize (Zea mays L.) population consisting of 184 F-2 individuals from the cross, Huangzao 4 X Ye 107. The 184 F-3 families were evaluated in the field under well-watered and drought-stressed regimes in Shanxi Province of China. The objectives of the study were to identify genetic segments responsible for the expression of anthesis-silking interval (ASI), ear setting and grain yield, and to examine if the quantitative trait loci (QTLs) for ASI or yield components can be used in marker-assisted selection (MAS) to improve grain yield under drought conditions. Results showed that under well-watered and drought-stressed regimes, three and two QTLs involved in the expression of ASI were detected on chromosomes 1, 2 and 3, and 2 and 5, respectively. Under well-watered regime, two QTLs for ear setting were detected on chromosomes 3 and 6, explaining about 19.9% of the phenotypic variance, and displayed additive and partial dominant effects, respectively. Under drought-stressed condition, four QTLs for ear setting were detected on chromosomes 3, 7 and 10, which were responsible for interpreting 60.4% of the phenotypic variance, and showed dominant or partial dominant effects. Under well-watered condition, four QTLs controlling grain yield were identified on chromosomes 3, 6 and 7, while five QTLs were identified under drought stress on chromosomes 1, 2, 4 and 8. The gene action was of additive or partial dominant effects, and each QTL could explain 7.3% to 22.0% of the phenotypic variance, respectively. Under drought conditions, ASI and ear setting percentage were highly correlated with grain yield, which can be used as secondary traits for grain yield selection. Based on linked markers detected and gene action analyzed, an MAS strategy for yield improvement under drought condition could be established, which consists of QTLs contributing to decreased ASI and to increased ear setting and grain yield, respectively.

Effects of Aphelenchoides besseyi Infection on Yield Traits of Different Rice Varieties (Lines)

[Objective] This study aimed to reveal the effects of Aphelenchoides besseyi infection on different rice varieties（lines）.[Method] By field observation and indoor phenotypic investigation,four conventional japonica rice varieties（lines） and japonica rice restorer line R161 under natural onset conditions were observed and analyzed.[Result] After being infected by A.besseyi,different rice varieties（lines）exhibited various symptoms.Specifically,Ning 1707,Ning 1818,Zhendao 88 and Nanjing 9108 had withered leaf tips and exhibited the symptoms of ＂small grains and erect panicles＂;japonica rice restorer line R161 only had withered leaf tips without symptoms of ＂small grains and erect panicles＂,and the withering symptoms occurred in flag leaf tip,whole flag leaf and top second leaf,respectively.After being infected by A.besseyi,all the experimental materials could sprout normally,but their plant height,panicle length,seed-setting rate and 1 000-grain weight were affected to varying degrees.In addition,after being infected by A.besseyi,various symptomatic tissues of R161 exerted different effects on rice yield.Especially,panicles with withered and twisted whole flag leaf were most affected.[Conclusion] This study provided the basis for further exploration of the damages of A.besseyi infection to rice and development of corresponding control measures.

Correlation and Principal Component Analysis on Main Agronomic Traits of New Waxy Corn Varieties

[Objective] This study was conducted to provide certain theoretical reference for the comprehensive evaluation and breeding of new fresh waxy corn vari- eties. [Method] With 5 good fresh waxy corn varieties as experimental materials, correlation analysis and principal component anatysis were performed on 13 agronomic traits, i.e., plant height, ear position, ear weight, ear diameter, axis diameter, ear length, bald tip length, ear row number, number of grains per row, 100-kernel weight, fresh ear yield, tassel length, and tassel branch number. [Result] The principal component analysis performed to the 13 agronomic traits showed that the first three principal components, i.e., the fresh ear yield factors, the tassel factors and the bald top factors, had an accumulative contribution rate over 87.2767%, and could basically represent the genetic information represented by the 13 traits. The first principal component is the main index for the selection and evaluation of good corn varieties which should have large ear, large ear diameter but small axis diameter, i.e., longer grains, larger number of grains per ear, higher, 100-grain weight and higher plant height. As to the second principal component, the plants of fresh corn varieties are best to have longer tassel and not too many branches, and under the premise of ensuring enough pollen for the female spike, the varieties with fewer tassel branches shoud be selected as far as possible. From the point of the third principal component, bald tip length affects the marketing quality of fresh corn, and during fariety evaluation and breeding, the bald top length should be control at the Iowest standard. [Conclusion] The fresh ear yield of corn is in close positive correlation with ear weight, 100-grain weight, ear diameter, number of grains per row and ear length, and plant height also affects fresh ear yield.

Effects of the Application of Controlled Release Nitrogen Fertilizer on Rapeseed Yield, Agronomic Characters and Soil Fertility

In order to study the effects of controlled release nitrogen fertilizer （CRNF） application on rapeseed, a simulated experiment was carried out with 3 types of paddy soils in Dongting Lake area for 4 consecutive years of applying CRNF under double rice cropping system after planting rapeseed crop in the fallow season. The effects of CRNF application on rapeseed yield, agronomic characters and soil fertility were studied in this paper. The results showed that CRNF application improved the growth of rapeseed plant and increased rapeseed yield of CRNF treatments in the purple calcareous clayed paddy soil （PCS） and alluvial loamy paddy soil （ALS） which respectively increased by 12.2% and 9.8% compared with applying urea, re- spectively. The rapeseed yield in 70% CRNF treatment obviously decreased com- pared with urea treatment. The contents of available N and organic carbon in soil increased by 25.0% and 3.2% in CRNF treatment in the ALS after rapeseed crop, respectively; and available N increased by 13.5% in the PCS. Both rapeseed yield and soil fertility in CRNF treatment and 70% CRNF treatment were lower than those in CK treatment in the reddish yellow clayed paddy soil （RYS）. The results al- so indicated that the functions of CRNF application on rapeseed yield increase and soil nitrogen fertility improvement were very obvious in the PCS and ALS.

Correlation Analysis and Path Analysis between Yield and Yield-Related Traits of Yunmai 52

[Objective] This study was tween yield-related traits and yield of conducted to understand the relationship be- Yunmai 52 which is a high-quality high-yield multi-resistant new wheat variety, and make contribution of yield-related traits to the yield of Yunmai 52 clear. [Method] Wheat variety regional trial data in Yunnan Province in 2005-2007 were subjected to correlation analysis and path analysis in the paper. [Result] Correlationanalysis showed that the yield of Yunmai 52 was in- very significant positive correlation with spikelet number per ear, maximum tiller number and grains per ear （r=0.726^＊＊, 0.717^＊＊ and 0.695^＊＊, respectively）, in signif- icant positive correlation with 1 000-grain weight （r=0.491^＊）, but in significant nega- tive correlation with sterile spikelet number per ear, and in non-significant correlation with basic seedlings, effective ears and percentage of ear bearing tillers. Partial correlation analysis showed that the yield of Yunmai 52 was in very significant posi- tive correlation with spikelet number per ear （r=0.711^＊＊）, significant positive correla- tion with 1 000-grain weight （r=0.641 =）, but in non-significant correlation with other 6 traits. Path analysis showed that spikelet number per ear （P=-0.595）, maximum tiller number （P=0.462） and t 000-grain weight （P=0.263） had more contribution to yield of Yunmai 52. [Conclusion] Therefore, in extension and application of Yunmal 52 that is a high-quality high-yield multi-resistant new wheat variety, supply of fertilizer and water should be increased in tillering stage and jointing stage, to ensure its characteristics of high tilledng ability and large ear, as well as high 1 000-grain weight, and coordinated development of other yield-related traits is beneficial to im- provement of yield of Yunmai 52.

QTL Mapping of Yield and Yield Components for Elite Hybrid Derived-RILs in Upland Cotton

A population of 180 recombinant inbred lines （RILs） was developed by single seed descended from the cross of high yield Upland cotton （Gossypium hirsutum L.） varieties Zhongmiansuo12 （ZMSI2） and 8891, the two parents of Xiangzamian2 （XZM2）. A genetic linkage map consisting of 132 loci and covering 865.20 cM was constructed using the RIL population chiefly with SSR markers. Yield and yield components were investigated for RILs in three environments in China. The purpose of the present research was to analyze the relationship between yield and its components and to map QTL for yield and yield components in cotton. QTL were tagged with data sets from single environment （separate analysis） and a set of data from means of the three environments （joint analysis）. A total of 34 QTL for yield and yield components were independently detected in three environments, whereas fifteen QTL were found in joint analysis. Notably, a stable lint percentage QTL qLP-A10-1 was detected both in joint analysis and in two environments of separate analysis, which might be of special value for marker-assisted selection. The QTL detected in the present study provide new information on improving yield and yield components. Results of path analysis showed that bolls/plant had the largest contribution to lint yield, which is consistent with the mid-parent heterosis value in F1. Accordingly, in cotton breeding, bolls/plant can be considered first and other yield components measured as a whole to implement variety enhancement and hybrid selection of cotton.

Effects of Plastic Film Mulching on Physical Characters of Soil and Yield and Yield Components of Sweet Potato

Field experiments were carried out to study the effects of plastic film mulching on soil physical characters, including soil temperature, soil moisture content and soil bulk density, and yield and yield components of sweet potato. The results showed that plastic filming mulching increased soil temperature. Considering the soil temperature-increasing effect, the treatments ranked as black plastic film treatment 〉 white plastic film treatment 〉 control. However, with the deepening of soil layer, the warming effect of plastic film mulching was weakened. Black or white plastic film mulching was conducive to low T/R value, especially in the early growth stage of sweet potato. Plastic film mulching significantly improved the storage root yield of sweet potato. In terms of yield-improving effect, the treatments ranked as black plastic film treatment 〉 white plastic film treatment 〉 control. The storage root num- ber per plant showed a downward trend, but the weight of single storage root was increased.

Effects of Vermicompost on Agronomic Characters and Yield and Quality of Flue-cured Tobacco

The effects of vermicompost on the agronomic characters and yield and quality of flue-cured tobacco were investigated. The results showed that, the field growth periods of various treatments were 117-118 d, 1-2 days longer than that of the CK. The numbers of effective leaves of the treatments applied with vermicompost were 0.1-0.3 leaf more than the CK. The highest yield and the highest proportion of high-grade tobacco occurred in treatment 3 as 2 095.5 kg/m^2 and 49%, respectively, which were higher than those in the CK by 6.58 kg and 5.3%. In conclusion, the treatment with the application of vermicompost at 7 500-10 500 kg/hm^2 was the best.

The Effect of Sowing Date and Density on the Characters and Yield of Maize in Chongqing

In order to investigate the most suitable sowing period and the optimum planting density of new com variety ‘Yudan 30＇ In Chongqing region, using split plot experiment design, the effect of sowing date and planting density on main a- gronomic characters and yield of maize in the field was studied. The results showed that in Chongqing, the delay of sowing date could shorten the fertility peri- od, and reduce 100-grain Weight and yield, but could increase plant height and ear height, panicle traits did not change significantly. With the density increasing, plant height and ear height also increased, while ear length, ear diameter, stem diameter, row number and kernel number also decreased. 100-grain weight and yield also in- creased with the increase of density, but to a certain threshold, yield and 100-grain weight decreased with the increase of density. The yield of 3 sowing periods pre- sented as AI〉A2〉A3, the yield of 4 kinds of density presented as B3〉EH〉B2〉B1, and the yield under sowing time and density interaction presented as AIB3〉A1B4〉 A2.B3〉A2.B4〉A3B3〉 A3B4〉A2.B2〉A1BI〉A2BI〉A3BI. So proper eady sowing and increase of planting density could raise the yield of maize per unit area, and AIB3 was the optimum planting configuration in Chongqing area.

Effects of Soil Amendment on Growth,Yield and Output of Flue-cured Tobacco in South Anhui Province

[Objective] The aim of this study was to evaluate the effects of soil amend- ment composed of biochar and inorganic mineral material on growth and develop- ment, yield and output value of flue-cured tobacco in South Anhui Province. [Method] A field plot experiment was conducted. The agronomic traits, yield and output value, as well as appearance quality and flavor of flue-cured tobacco were evaluated. [Re- suit] The soil amendments composed of biochars and inorganic mineral materials could significantly increase plant height, stem diameter, leaf size, yield and output of flue-cured tobacco, as well as proportion of first-grade tobacco leaves at the middle and late growth period. The yield in the X3 treatment group （70% T20 ＋ 30% ZC） was highest, and it was higher than that in the control group by 398 kg/hm2. Com- pared with that in the control group, the output of flue-cured tobacco in the X3 treatment group was increased by 10 290 yuan/hm2. In terms of appearance quality and flavor, the flue-cured tobacco leaves in the soil amendment treatment groups were all better than those in the control group. [Conclusion] The application of soil amendment composed of biochar and inorganic mineral material is an effective mea- sure to improve tobacco-growing soil, promote tobacco growth and development, im- prove tobacco yield and output and improve tobacco leaf quality in South Anhui re- gion.

Comprehensive Evaluation of Yield Characters and Quality Characters of New Cotton Varieties in Mid-south Area of Hebei

The yield characters and quality characters of several new cotton varieties in the mid-south area of Hebei Province were comprehensively evaluated in this pa- per. In different ecological environments, the single-boll weight of tested cotton vari- eties had the biggest variation coefficient among yield characters and micronaire value had the biggest variation coefficient among fiber quality characters. Path analy- sis indicated that the direct path coefficients of various characters had the flowing order, lint percentage〉 number of bolls per plant〉 single-boll weight〉 seed index among yield components and uniformity index 〉 fiber specific strength〉 micronaire value〉 elongation rate〉 upper half staple length among fiber quality characters. Principal component analysis indicated that the top three principal components contributed 8.263% of accumulated variance, basically reflecting the vast majority of informations of 10 main characters in tested cotton varieties.

Combining Ability Analysis on Yield Traits of Recombinant Inbred Lines in Hybrid Rice

A population of 140 recombinant inbred lines at F8 generation were obtained after seven successive generations of self-pollination using single seed descent（SSD） method from the F2 hybrids of three-line restorers Luhui 8258 with high combining ability and Yanghui 34. Then, the 140 inbred lines obtained above and their parents Luhui 8258 and Yanghui 34 were crossed with three different types of cyto-plasmic male sterile（CMS） lines（Gang 46 A, Ⅱ-32 A and Lu 98A） according to NCⅡ design. The resulting 426 combinations were planted at Deyang and Suining bases to test the combining ability and inheritance of five yield traits： yield per plant, panicle number per plant, filled grain number per panicle, seed setting rate and 1 000-grain weight. The results showed that the variances of both general and specific combining abilities of the five traits all reached a significant or extremely significant level at the two sites. The broad and narrow heritability of the yield traits（except 1 000-grain weight whose broad and narrow heritability were both over70%） were all below 50% at the two experimental bases, suggesting that the four traits were easily subjected to environment influence. Very significant positive correlation of general combining ability was found between yield per plant and other traits except 1 000-grain weight. The general combining ability variance showed a normal distribution among the recombinant inbred lines at two sites, right in line with inheritance of quantitative traits. So, the genes controlling rice general combining ability can be targeted by QTL mapping.

Effects of Key Agricultural Measures of Mechanized Direct Seeding Technology on Rapeseed Yield in Chengdu Plain

Mechanized direct sowing of rapeseed is a labor-saving and highly-efficient culture technique. In order to explore high-yield cultivation techniques suitable for Chengdu Plain, effects of several key agronomic measures＇, such as sowing date, density and N fertilizers, on development and yield formation were studied by strip and split plot experiment of three factors. The research showed that optimal condi- tions for direct seeding technology can be achieved provided with scientific sowing date, density and appropriate N fertilizers, and the research showed that rapeseed yield reached the peak at 320 g/m2, when sowing date was on September 3th, sow- ing density was 30 plant/m2, and nitrogen fertilizer was 27 g/m2.

Effects of Spraying Deltamethrin on Agronomic Traits and Yield of Soybean

At the seedling and beginning flowering stages,2.5% deltamethrin EC was sprayed to control the pests in summer soybean,and its effects on agronomic traits and yield of soybean were analyzed.The results showed that compared with the control,the plant height,branch number,effective pod number,grain number per plant,grain weight per plant,100-grain weight and yield of Qihuang 34 significantly increased by 9.3%,25.8%,15.8%,26.8%,33.2%,9.1% and 33.0%,respectively,while those of Qihuang 35 increased by 13.8%,10.0%,15.8%,16.9%,11.6%,6.0%and 16.9%,respectively;the noneffective pod number of Qihuang 34 and Qihuang35 significantly decreased by 18.5% and 38.7%,respectively.The spraying of 2.5%deltamethrin EC showed no significant effects on the other agronomic traits of the two cultivars.