Study of gene effects for cotton yield and Verticillium wilt tolerance in cotton plant (Gossypium hirsutum L.)

Verticillium wilt (VW), caused by Verticillium dahliae Kleb., is a destructive disease of cotton (Gossypium hirsutum L.). The use of resistant cultivars has long been considered the most practical and effective mean of control. The aim of this work was to study the quantitative genetic basis of Verticillium wilt resistance in Upland cotton by using five genotypes and their possible crosses without reciprocals selecting simultaneously for resistance and desirable agronomic characteristics. Five cotton cultivars and 10 F1s from half-diallel crosses were analyzed for VW resistance. The seed cotton yield, the number of bolls/ plant, and boll weight were measured and Verticillium wilt index (VWI) was estimated during two crop seasons in two different sites each year always on plots with naturally infested soil. Genetic components of variance were analyzed using the Hayman model. Analysis of variance for all characters showed significant differences between genotypes, without genotype-site interaction in most cases. Both, additive genetic variance component (D) and dominance genetic variance components (H1 and H2) were presented in all characters, except for VWI. D was the most important component for boll weight and VWI. Boll weight was the most correlated character with seed cotton yield and VWI. Broad sense heritability was high for boll weight and VWI, moderate for seed cotton yield and low for bolls per plant. Narrow sense heritability was moderate for boll weight, and high for VWI.     

Determining Selection Gains and Discriminating Environments via GGE Biplots

Abstract

Genetic variation is the basis for meaningful selection; thus, the use of locations that discriminate or result in greater variation among genotypes, for a trait or trait package should promote accurate selection of superior genotypes. The objectives of this study were to quantify the gains by selection in discriminating locations using superior parents for single or multiple-trait populations. GGEbiplot software was used to identify two levels (high and low) of discriminating locations for each of three distinct populations of cotton (Gossypium hirsutum L.). Populations were obtained by crossing parents recommended by a least squares means analysis for each population criteria, which included parents/populations selected for: (a) lint yield; (b) fiber micronaire, length, strength, uniformity, and elongation; and (c) lint yield, lint percent, fiber micronaire, length, and strength. F₂ plants in 2003 and F_2:3 plants in 2004 were planted in the high and low discriminating locations for each selection criteria. Heritability estimates (h²) were calculated by regressing the F_2:3 plants on their F₂ parents. Genotypic variance was greater among F_2:3 progeny in discriminating environments compared with non-discriminating environments, regardless of population criteria. Heritability was greater in the population containing fiber traits compared with yield. The results of this study suggest that using discriminating locations during the selection phase of a breeding program can increase genotypic variance and enhance selection accuracy.     

棕絮棉18个性状的杂种优势研究

本文利用3个亲本配制的6个杂交组合。研究了棕絮棉的生育期、株高、果技数、总果节数、木技数、木技铃、总铃数、单铃重、衣分、亩籽棉、株皮棉、2．5％跨长、整齐度、比强度、伸长率、麦克隆值等18个性状的中索优势、超亲优势和竞争优势。并据此初步选育出产量、纤维品质较为优良的杂种棉一个。     

A technique of cotton bale laydown using clustering algorithm

A new technique of cotton bale management using clustering algorithm has been proposed. The method is based on the grouping cotton bales of similar kind into respective categories using k-mean square clustering algorithm. A set of 500 cotton bales were clustered into 5 categories by minimizing the total within-group squared Euclidean distance around the 5 centroids. In order to cluster bales of different categories, 8 fibre properties, viz., strength, elongation, upper half mean length, length uniformity, short fibre content, micronaire, reflectance and yellowness of each bale have been considered. Once the bales are clustered into different categories, it is possible to prepare consistent bale mix for consecutive laydowns on the basis of frequency relative picking method.     

Integrated management of Fusarium and Verticillum wilts of cotton in China

Fusarium and Verticillium wilts of cotton, which are widely distributed, generally occur concurrently and cause serious losses in cotton production in China. A general survey in 1982 showed that about 16% of Chinese cotton-growing regions were infested and could be demarcated into heavily, moderately and lightly infested regions. The estimated annual loss was about 100 000 tons of lint cotton. The tactics used for integrated management have been developed. Three biotypes of Fusarium oxysporum f. sp. vasinfectum have been identified. Different virulent strains have been found in both F. oxysporum f. sp. vasinfectum and Verticillium dahliae in different regions. Since 1951, 47 Fusarium-wilt-resistant and Verticillium-tolerant cultivars have been developed and grown in heavily infested regions. About 50% of the potential loss from cotton wilt diseases is saved annually. By using an organic solvent infusion (OSI) technique, fungicides such as carbendazim or ethylethene thiosulphonate can easily penetrate into dormant seeds; thus, a better disinfection of internal seed-borne pathogens is obtained. Seed coating treatment with a combined formulation of the systemic fungicides carbendazim and quintozene and the insecticide carbofuran provides a good integrated control of seed- and soil-borne diseases as well as of cotton aphids, thrips and soil insects at the seedling stage. More plant growth and yield of lint cotton have been obtained in comparison with the untreated control in field tests.     

Leaf carbon isotope discrimination,ash content and K relationships with seedcotton yield and lint quality in lines of Gossypium hirsutum L.

In a two-year (2005–2006) study conducted at three sites in central (Larissa) and northern (Alexandroupolis, Thessaloniki) Greece, we aimed to investigate the relationships between seedcotton yield and lint quality with leaf physiological traits (carbon isotope discrimination-Δ, ash content and K concentration). Eighteen lines with their original cultivars (Christina, Flora, Corona) were tested under the ultra-low density of 1.2 plants m⁻². In combined data over years, a significant, positive correlation between seedcotton yield and Δ or ash content was found only in the driest and lowest-yielding site (Larissa), indicating that genotypes that keep their stomata open and in turn exhibit the highest Δ values, had an advantage in such environments. In pooled data from the two most productive sites (Thessaloniki and Alexandroupolis), which had the highest Δ and ash content values, evidenced a negative correlation between seedcotton yield and both physiological traits. Seedcotton yield was negatively related with leaf K concentration in Larissa and Alexandroupolis but no significant relationship was found in Thessaloniki where leaf K concentration was below adequacy limit. Δ was positively related with ash content which suggests that the latter could be a putative surrogate of Δ. Negative correlation between Δ and leaf K concentration was found in two out of three sites (Larissa and Thessaloniki) as well as between ash content and K in one site (Larissa). These findings suggest that K accumulation in leaves is not just a passive procedure via transpiration stream. Significant, linear relationships of each physiological trait between sites showed that genotypic ranking was constant in the three sites, an indication of heritability. Ash content had the highest significance levels and correlation coefficients. Even though significant genotypic differentiation was observed for the three physiological and two of the lint quality traits (i.e. fibre length, micronaire) determined in Alexandroupolis, only a weak, negative relationship between fibre length and leaf K concentration was evident. In sum, leaf physiological traits (Δ, ash content and K concentration) could not be reliably used for yield selection in cotton owing to site-specific effects, which prejudice the yield–physiological traits relationship. Ash content–Δ relationship merits further research in order the former to be established as a putative surrogate of Δ.     

Analysis on genetic contribution of agronomic traits to total sugar in flue-cured tobacco (Nicotiana tabacum L.)

To uncover the genetic contributions of agronomic traits to content of total sugar (TS) and find indicator traits for indirect selection on TS in the flue-cured tobacco (Nicotiana tobacum L.), multivariable conditional analysis was conducted based on a genetic model containing additive–dominance and their interactions with environments. Fourteen cultivars (or breeding lines) and derived 41 F₁ crosses were grown at four locations in Yunnan province, China. Significant phenotypic contribution to TS was detected for six agronomic traits, plant height (PH), girth of stem (GS), internode length (INL), number of leaves (NL), length of middle leaves (LML) and width of middle leaves (WML). There was large contribution of additive effects due to each of the five agronomic traits (PH, GS, INL, LML and WML). The contribution ratio of dominance effect was high due to PH. By serving as high contributor of additive effects to TS and having high ratios of additive variance to phenotypic variance, INL and PH could be used as indicative agronomic traits for selecting breeding lines with suitable TS. Among the six agronomic traits, PH had the highest contribution to dominance effects of TS for most F₁ crosses, and could be used for selecting the crosses with suitable TS.     

不同生态条件下杂交棉产量与品质性状稳定性研究

2009-2010年,在湖南农业大学、澧县、大通湖、省棉科所、南县、君山、安乡7个区试点。对包括湘杂棉8号在内的共11个杂交棉品种组合进行了产量性状和纤维品质性状的稳定性分析。结果表明：从不同生态条件下年际间杂交棉产量性状、纤维品质性状变异系数来看,铃数和麦克隆值变异系数较大,衣分和整齐度变异系数较小;从不同生态条件下年际间杂交棉产量性状、纤维品质性状相关性分析来看,皮棉产量与铃数、衣分呈极显著性正相关,与铃重呈负相关,纺纱均匀性指数与比强、纤维长度成极显著的正相关,与麦克隆值呈极显著性负相关。,衣分值是产量性状中最稳定的,整齐度是纤维品质性状中最稳定的。     

早熟棉F1代22份材料主要性状的综合评价分析

通过对江西省棉花研究所育种课题组利用早熟棉品种与高产优质的中熟棉材料进行杂交的F1代22份材料,采用主成分、聚类和相关性分析方法进行12个主要性状综合评价分析,以期筛选出早熟、高产、优质的棉花新品种或组合。统计分析结果表明,22份材料的各个性状的表现存在较大差异,籽棉产量的变异系数最大,生育期和纤维整齐度指数变异系数较小。相关性分析结果表明,生育期与马克隆值、纤维上半部平均长度、整齐度指数、伸长率均呈正相关,纤维上半部平均长度与马克隆值、断裂比强度相关性达到极显著水平。主成分分析结果显示,前4个主成分特征值大于1,累计贡献率达到70.713%。聚类分析结果表明,在遗传距离5.0处,22份材料划分为5个类群,第IV类和第V类产量高、品质好,其中第V类生育期短、植株矮。本研究通过综合评价分析筛选出早熟高产优质材料2份,可进一步育成早熟棉新品种进行示范推广;此外还筛选出高产材料3份,优质材料2份,早熟材料1份,可进一步改良利用。     

氮肥和氮磷钾配比对科棉1号产量和品质的影响

以Bt转基因抗虫棉科棉1号为试验材料．研究了氮肥和氮磷钾配比对皮棉产量和纤维品质的影响。研究结果表明．施氮量375kg／hm^2．氮磷钾配比1：0．4：0．8能够有效增加单株成铃数．提高铃重．提高皮棉产量．获得的皮棉产量最高．这到1650．43kg／hm^2。随着氮磷钾配比的提高．当提高到1：0．8：1．6时。皮棉产量出现下降的趋势。施氮量375kg／hm^2．氮磷钾配比1：0．8：1．6能够有效地促进纤维品质的改善．主要表现为：马克隆值有所优化．更加接近A级．成熟度和长度整齐度均有所提高。断裂比强度显著增加．短绒率有所降低。     

Prediction of rotor spun yarn strength from cotton fiber properties using adaptive neuro-fuzzy inference system method

In this study, we present the application of a hybrid neuro-fuzzy system for the prediction of cotton rotor spun yarn strength from cotton fiber properties. The proposed system possesses the advantages of both artificial neural networks and fuzzy logic, and is thus more intelligent. HVI (high volume instrument) and Uster AFIS (advanced fiber information system) fiber test results are used to train the neuro-fuzzy inference system. We also study the degree of impact of each fiber property on the rotor spun yarn strength. Fiber strength, upper half mean length, length uniformity and yarn count have a positive impact whereas micronaire, yellowness and short fiber content have a negative impact on rotor spun yarn strength.     

Disease Tolerance in Helianthus petiolaris : A Genetic Resource for Sunflower Breeding

Abstract

Argentina is a major sunflower producer in the world, with crop acreage of 2?2.7 million ha in the last four years. Sunflower crop yield is often influenced by sanitary constraints, mainly fungal pathogens. Helianthus petiolaris is a wild species native to North America established in central Argentina displays a high tolerance to a number of fungal diseases and insects. Controlled crosses of this species with sunflower demonstrated that H. petiolaris constitutes a valuable genetic variability source for sunflower breeding to improve tolerance to rust (Puccinia helianthi), white rust (Albugo tragopogonis), verticillium wilt (Verticillium dahliae), powdery mildew (Erisiphe sp.) and the sunflower moth (Rachiplusia nu). This places H. petiolaris in an outstanding position as a genetic resource since different important traits could be transferred to the crop through interspecific hybridization.     

Fungicidal effect of hydroxytyrosol-rich preparations from olive mill wastewater against Verticillium dahliae

Verticillium dahliae cannot be reached by many fungicides during its parasitic phase inside the plants and few fungicides are available to cure plants once they are infected by this pathogen. A hydroxytyrosol-rich (29.27% weight/dry weight) olive mill wastewater (HROMW) and a hydroxytyrosol-rich (52.67% weight/dry weight) extract (HRE) were prepared from fresh olive mill wastewater (FOMW) using hydrolysis and post-hydrolysis purification processes, and were tested as bio-fungicides. The HROMW and HRE showed strong fungicidal activity in vitro against V. dahliae with minimal fungicidal concentrations (MFCs) of 28–56 mg L⁻¹ (dry weight). The HROMW and HRE at 15 g L⁻¹ (dry weight) resulted in a reduction in the viability of V. dahliae by >4 log units after 30 min of contact time according to European Standard EN 1275 (1997) standard method. In tomato pot growth experiments incorporation of HROMW and HRE into the soil reduced significantly Verticillium wilt disease incidence by 86 and 83% and wilt severity by 86 and 84.5%, respectively, compared to untreated plants.     

The potential contribution of wild barley (Hordeum vulgare ssp. spontaneum) germplasm to drought tolerance of cultivated barley (H. vulgare ssp. vulgare)

Improving drought tolerance has always been an important objective in many crop improvement programs and is becoming more important as one way of adapting crops to climate changes. However, due to its complexity, the genetic mechanisms underlying the expression of drought tolerance in plants are poorly understood and this trait is difficult to characterize and quantify. This study assessed the importance of the wild progenitor of cultivated barley, Hordeum spontaneum C. Koch, in contributing developmental and yield-related traits associated with drought tolerance and therefore its usefulness in breeding for improved adaptation to drought stress conditions. Fifty-seven fixed barley lines derived from crosses with two H. spontaneum lines (41-1 and 41-5) were evaluated in Mediterranean low rainfall environments with 10 improved varieties and three landraces for grain yield, developmental and agronomic traits. The study was conducted for three years (2004–2006) in a total of nine environments (location–year combinations), eight in Syria and one in Jordan, which were eventually reduced to seven due to a large error variance in two of them. There was significant genetic variation among the genotypes for most of the traits measured, as well as differential responses of genotypes across environments. Traits such as peduncle length, peduncle extrusion and plant height were positively correlated with grain yield in the dry environments. Differences in phenology were small and not significantly correlated with differences in grain yield under stress. Performances at the three highest yielding environments were much more closely correlated than those at the four stress environments. The GGE biplot analysis allowed identification of genotypes consistently best adapted to the lowest yielding environments and confirmed the existence of unique environments for identifying better adapted genotypes in the low rainfall environments of Syria. The top yielding lines in the driest of the seven environments derived mostly from crosses with H. spontaneum 41-1, while most of the improved varieties showed a positive genotype by environment (GE) interaction with the highest yielding environments. The results of the field experiments indicated that there was variation for grain yield under drought stress among barley genotypes, and that some of the lines derived from H. spontaneum had consistently superior specific adaptation to the range of severe stress conditions used in this study. The usefulness of H. spontaneum in breeding programs for stress conditions is likely to increase in view of the predicted increase in the occurrence of high temperatures and droughts.     

Quantitative trait loci for leaf length in perennial ryegrass (Lolium perenne L.)

Leaf length is an important trait for forage grasses. Molecular marker development offers the opportunity to identify Quantitative Trait Loci (QTLs) and to begin to dissect the genetic regulation of complex traits. The objective of this study was to look for QTLs for leaf length and related traits (plant height, lamina and sheath lengths, leaf elongation rate and leaf elongation duration) in the progeny of a cross between two genotypes of Lolium perenne L. with contrasting leaf length. Measurements were performed in a plant nursery in autumn and spring, and in a heated greenhouse in winter. A high level of variability and heritability was observed for all traits. Lamina lengths at different dates were moderately but significantly correlated. For all traits, QTLs were found and explained between 0·08 and 0·44 of phenotypic variance. Although different leaf length QTLs were found at different dates, linkage groups two, four and seven were particularly important.     

近5年新疆陆地棉纤维品质情况分析

以2015～2019年我国棉花纤维品质公证检验检测数据为研究内容,分析了新疆棉花品质状况和演变趋势.结果表明,新疆总体棉花纤维长度呈整体上升趋势,年均上升0.13 mm,其中2015～2018年持续上升、2019年有所下降;断裂比强度整体上升了0.18 cN/tex,年际间略有波动,断裂比强度强级及以上占比有所上升;纤...     

Evaluation of potato clones for severity of Verticillium wilt, yield and specific gravity in Maine

In 1994 and 1995, the effect of Verticillium wilt, caused byVerticillium dahliae andV. albo-atrum, on tuber yields, number and weight of U.S. No. 1 and B size tubers, and specific gravity was studied in northern Maine, an area with a short growing season. Seven clones (four resistant and three susceptible) were evaluated in a split-plot design with three replications. Clones were the whole-plot factor, and seed pieces in sub-plots were either uninoculated or inoculated with 50 ml of 4 × 10⁴ cfu/mlVerticillium spp. at planting. Individual plants were scored for Verticillium wilt symptoms before harvest on a 1= <3% wilt to 10= >97% wilt. Differences among clones for wilting and specific gravity were significant. The inoculation treatment had no effect on any of the tuber traits measured. However, there were significant clone x inoculation interactions for most tuber traits. Reductions in yield, weight and number of U.S. No. 1 potatoes, and specific gravity were greater in the Verticillium wilt susceptible clones than in the resistant clones. These results suggest that breeding clones with resistance toVerticillium spp. will reduce yield losses, while maintaining tuber size and specific gravity under disease pressure.     

粳型杂交稻稻米外观品质性状的遗传效应研究

 以宁67A等4个粳型不育系与K1722等9个粳型恢复系进行不完全双列杂交，采用禾谷类作物胚乳品质性状的遗传模型及其分析方法，对粳型杂交稻稻米外观品质性状进行了遗传研究。结果表明，稻米的糙米长、糙米长宽比、糙米长厚比主要受母体加性效应控制，而透明度以母体加性效应和种子直接加性效应为主；垩白率、垩白度主要受种子直接加性和母体加性效应所控制，以种子直接加性效应为主。多数性状的种子直接遗传率、细胞质遗传率和母体遗传率均达显著或极显著水平，其中糙米长、糙米长宽比、糙米长厚比、透明度以母体遗传率为主，垩白率、垩白度以种子直接遗传率为主。另外，根据性状的遗传效应预测值对各亲本的育种利用价值作了评价     

Estimation of genetic parameters for characters related to potato propagation by true seed (TPS) in an andigena population

Genetic variances were estimated for a population ofSolarium tuberosum L. subsp.andigena, selected for adaptation to north temperate climatic conditions. Estimates for 15 traits, including some unique to true seed (TPS) propagation, were obtained from trials conducted under short day conditions in Peru. Only non-additive variance was found for yield, but heritability estimates were relatively high for tuber number and tuber size. The results indicated that yield could be increased through selection utilizing additive variance for the component traits, especially tuber size. Estimates of genetic variability for tuber uniformity were low. TPS yield was positively correlated with most other traits except tuber number.     

Stand establishment and early field vigour variation in a tropicalised shrunken-2 maize population

Low field emergence and early field vigour are major problems in shrunken-2 maize (sh-2). The genetic variability for stand-ability and early field vigour in a shrunken-2 maize population previously improved for adaptability to a tropical environment was investigated using a Design I mating system in which 40 randomly sampled males were crossed to four randomly sampled plants that served as females. Plants of the 160 crosses, representing full- and half-sib relationships, were evaluated in four sets, each composed of 40 crosses derived from 10 males during two growing seasons. Experimental design was randomized complete block with three replications. Difference in Emergence Index (EI) was not significant between the two seasons. Emergence Percentage (E%), Emergence Rate Index (ERI), and early field vigour traits viz. vigour score and seedling height determined at 28 days after planting (DAP) were, however, significantly (P < 0.05–P < 0.01) better in the first growing season. For all traits, the ‘female/male’ item was significant (P < 0.01) while ‘male’ was mostly non-significant. ‘Season × female/male’ interaction was significant for stand establishment traits but not for early field vigour traits. Averaged over all traits, dominance variance was 8.2 times higher than additive variance. Genetic variation for stand establishment and early field vigour in the tropicalised shrunken-2 maize population would be best exploited through the development of inbred lines, hybrids and synthetics. Broad-sense heritability was 53.0% for E%, 36.0% for EI, 33.0% for ERI, 71.5% for vigour score and 90.0% for seedling height. One hundred-seed weight ranged between 82.0 and 182.0 mg but correlation coefficients between seed weight on one hand, and E%, EI, ERI, vigour score and plant height on the other hand, were low (mostly <0.30) and, in general, non-significant. Emergence percentage had the highest average genotypic correlation value with the other traits studied (Mean Absolute Value = 0.71 in the first season and 0.45 in the second season). Emergence percentage, determined 10 days after planting, thus has potential for use as a selection index for stand establishment and early field vigour.