The Effectiveness of HA-GGE Biplot Application in Analyzing the Data from the National Cotton Cultivar Regional Trial in the Yangtze River Valley

A large number of regional crop trials have demonstrated the ubiquitous existence of genotype × environment interactions (G×E), which make it complicated to select superior cultivars and identify the ideal testing sites. The GGE (genotype main effect plus genotype × environment interaction) biplot is the most powerful statistical and graphical displaying tool available for regional crop trial dataset analysis. The objective of the present study was to demonstrate the effectiveness of the biplot in evaluating the high and stable yields of candidate cultivars simultaneously, and in delineating the most adaptive planting region, analyzing trial location discrimination ability and representativeness, and identifying the ideal cultivar and trial locations. The lint cotton yield dataset with nine experimental genotypes and 17 test locations (three replicates in each) was collected from the national cotton regional trial in the Yangtze River Valley (YaRV) in 2012. The results showed that: (1) the effects of genotype (G), environment (E), and genotype × environment interaction (G×E) were significant (P < 0.01) for lint cotton yield. Differences among environments accounted for 78.7% of the treatment total variation in the sum of squares, whereas the genotype main effect accounted for 8.7%, and the genotype × environment interaction accounted for 12.6%. (2) The “ideal cultivar” and “ideal location” view of the HA-GGE biplot identified Zhongcj408 (G2) and Nannon12 (G9) as the best ideal genotypes; Cixi in Zhejiang Province and Jiangling in Hubei Province were the most ideal locations.(3) The “which-won-where” view of the biplot outlined the adaptive planting region for each experimental cultivar. (4) The “similarity among locations” view clustered the trial locations into four groups, among of which the two outlier locations, Shehong (SH) and Chengdu (QBJ), located in Shichuan Basin in the upper reaches of YaRV, were clustered in one group, whereas the Nanyang (NY) of Henan Province at the northern edge of YaRV was singled out as a sole group. Such location clustering results implied an apparent association with the geographical environment.     

Leaf Temperature and Transpiration of Field Grown Cotton and Soybean under Arid and Humid Conditions

Abstract

Abstract : Cotton (Gossypium hirsutum L.) and soybean (Glycine max (L.) Merr.) cultivars were grown under arid (Urumqi, Xinjiang, China) and humid (Matsudo, Chiba, Japan) conditions to analyze their abilities to adapt to arid conditions in terms of transpiration, leaf movement and leaf temperature. Under the arid condition, the leaf temperature of the cotton cultivars was higher than that of the soybean cultivar and the air temperature. There was no significant difference in leaf temperature among the cotton and soybean cultivars under the humid condition. The flow rate of stem sap in the cotton cultivars under the arid condition was always higher than that in the soybean cultivar, and was largely affected by vapor pressure deficit (VPD). Under the humid condition, however, the flow rates of stem sap were lower in the cotton cultivars than in the soybean cultivars. These results indicate that cotton can avoid heat stress by the high transpiring ability possibly supported by well-developed root systems, which leads to higher drought resistance under the arid condition. Soybean would adapt to arid conditions by the combination of paraheliotropic leaf movement and reduced transpiration.     

Potassium distribution in root and non‐root zones of two cotton genotypes and its accumulation in their organs as affected by drought and potassium stress conditions

A rhizobox experiment was conducted to compare the differences of soil potassium (K) distribution and absorption between two cotton (Gossypium hirsutum L.) genotypes under drought and K‐deficit conditions. Treatments included two levels of water (drought and optimum soil moisture: 25% and 35% volumetric water content) and K fertilizer rates (0 and 0.48 g potash kg^?1 soil) applied to two cotton genotypes (namely HEG and LEG). Both the genotypes showed significant differences in total K accumulation without exogenous K addition. After absorption, soil content of the readily available potassium (RAK) decreased rapidly. This promoted the conversion of the mineral K into slowly available potassium (SAK). Drought significantly decreased the cotton growth and K use efficiency, and thereby reduced the effect of K fertilizer. Consequantly, the contents of RAK and SAK were greatly increased. However, K bioavailability was decreased under water stress conditions. Differences in root parameters and soil microorganisms between two cotton genotypes were significantly increased and had marked relations with available soil K contents. This study provides important information for understanding the mechanism of K use efficiency, especially under water and K stress.     

Electron Transport Through Photosystem II Is Not Limited By A Wide Range of Water Deficit Conditions In Field‐Grown Gossypium hirsutum

Despite exhaustive literature describing drought stress effects on photosynthesis in Gossypium hirsutum, the sensitivity of photosynthetic electron flow to water deficit is heavily debated. To address this, G. hirsutum plants were grown at a field site near Camilla, GA under contrasting irrigation regimes, and pre‐dawn water potential (Ψ_PD), stomatal conductance (g_s), net photosynthesis (P_N), actual quantum yield of photosystem II (Φ_PSII) and electron transport rate (ETR) were measured at multiple times during the 2012 growing season. Ψ_PD values ranged from ?0.3 to ?1.1 MPa. Stomatal conductance exhibited a strong (r² = 0.697), sigmoidal response to Ψ_PD, where g_s was ≤0.1 mol m^?2 s^?1 at Ψ_PD values ≤ ?0.86 MPa. Neither Φ_PSII (r² = 0.015) nor ETR (r² = 0.010) was affected by Ψ_PD, despite exceptionally low Ψ_PD values (?1.1 MPa) causing a 71.7 % decline in P_N relative to values predicted for well‐watered G. hirsutum leaves at Ψ_PD = ?0.3 MPa. Further, P_N was strongly influenced by g_s, whereas ETR and Φ_PSII were not. We conclude that photosynthetic electron flow through photosystem II is insensitive to water deficit in field‐grown G. hirsutum.     

Effect of Pathogen Synergistic Pathogenicity on Severity of Verticillium Wilt of Cotton

Verticillium dahliae is a soil-borne and vascular pathogen causing Verticillium wilt of cotton, which is one of the most severe diseases affecting cotton production in China. Recently, a soil-inhabiting opportunistic pathogen was isolated and identified as Scopulariopsis gossypii; it could infect the host through wounds and increase disease severity in combination with V. dahliae. S. gossypii was able to form conidia in a nutritionally poor substrate and had similar biological characteristics to other vascular pathogens, while ultrastructure observation also confirmed that it was present in vascular tissue of cotton plants and produced conidia. Nematode activity in soil could cause wounds on the surface of cotton roots resulting in infection by the pathogens. On the basis of our analysis of the biological characteristics and infection process of S. gossypii and its interactions with other pathogens in cotton plants, we propose establishing a research program for multipathogen-host interactions in the cotton rhizosphere, which will enable detailed investigation of the synergistic pathogenesis of S. gossypii and V. dahliae.     

陆地棉原生质体培养与植株再生

以陆地棉品种“珂字２０１”为材料,比较了ＩＡＡ＋ＫＴ和２,４－Ｄ＋ＫＴ在愈伤诱导和悬浮培养中的效应,结果表明：愈伤组织诱导中,ＩＡＡ和２,４－Ｄ表现为正效应,且２,４－Ｄ的效应强于ＩＡＡ;ＫＴ表现为负效应;胚性愈人务悬浮培养中;３种激素都表现出负效应。以胚性细胞悬浮系了原生质体的分离和培养试验,分离原生质体的最佳酶组合为纤维素酶３％＋果胶酶１．５％,原生质体培养的最佳激素为ＩＡＡ０．５ｍｇ／Ｌ＋Ｋ     

基因型对陆地棉花药离体培养反应的影响

对２７种棉花基因型的花药在离体培养中的反应进行了比较,结果表明：所有的基因型在合适的培养条件下均能高频率地形成愈伤组织,但不同基因型间愈伤组织诱导率和诱导量不同;再生植株的花药比原始亲本的花药易诱导出愈伤组织;品种间杂种表现出部分优势,但不明显。本试验中,仅鲁棉６号和Ｓｉｏｋｒａ１－３两个品种诱导获得了胚性愈伤组织、胚状体和再生植株,且二者之间也存在着差别。从基因型在棉花花药培养中的效应、外界调控对棉花不同基因型花药培养效果的影响、棉花花药培养与体细胞培养基因型差异的比较等三个方面进行了讨论,提出了棉花花药培养愈伤组织诱导和植株再生是受两套遗传基因控制的遗传性状,并提出了棉花组织培养植株再生的阈值问题     

澳洲野生棉种的子叶棉酚动态及与色素腺体形态的关系

对斯特提棉、南岱华棉、澳洲棉、纳尔逊氏棉和比克氏棉五个澳洲野生棉种在种子萌发过程中的子叶棉酚含量进行了测定和分析。结果表明,五个澳洲野生棉种子叶中的棉酚积累过程与无色素腺体陆地棉品种基本相似,其休眠种子和萌发２４ｈ以内的子叶均检测不到棉酚,为典型的低酚棉类型。当种子萌发４８ｈ以后,其子叶开始出现棉酚,但含量极低;在子叶开始出现棉酚１～２ｄ后,棉酚含量开始迅速增加,到种子萌发第９ｄ达到最大值。此外,讨论了澳洲野生棉种的子叶色素腺体延缓形成的组织结构与棉酚积累的关系,以及该性状的遗传调控机理等。