BROAD SENSE HERITABILITY AND GENOTYPE X ENVIRONMENT INTERACTION FOR CARBON ISOTOPE DISCRIMINATION IN FIELD-GROWN WHEAT
BROAD SENSE HERITABILITY AND GENOTYPE X ENVIRONMENT INTERACTION FOR CARBON ISOTOPE DISCRIMINATION IN FIELD-GROWN WHEAT
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DOI：
10.1071/ar9920921
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发表时间：
1992-01-01
影响因子：
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通讯作者：
RICHARDS, RA
中科院分区：
文献类型：
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作者：
CONDON, AG;RICHARDS, RA
碳同位素判别法（DELTA）可以综合评价叶片蒸腾效率的基因型差异，因此被认为是水分有限环境下育种中提高水分利用效率的一个可能的选择标准。在小麦中已经证明了DELTA的相当大的基因型变异，但是环境因素可能导致在植物干物质中测量的DELTA值发生更大的变化，这可能损害DELTA在育种计划中的有效使用。在这项研究中，我们评估了广义遗传力的DELTA和基因型x环境互作的意义DELTA在田间生长的小麦。另一个目的是确定最有效的生长阶段或植物部分来表征DELTA的基因型变异。20)生长在横跨南澳大利亚小麦带的一系列田间环境中。碳同位素的歧视，确定从7个州际小麦品种试验在1983年和1984年生长的未复制的谷物样品，并在几个植物部分从1985年至1988年在新南威尔士州西南部的四个地点进行重复实验。从这些重复的实验中，DELTA的广义遗传力以基因型平均值为基础进行计算（h2-DELTA（M））和单小区（h2-DELTA（p））。在从几种环境中取样的干物质中，早成干物质的平均DELTA值为21.0 × 10 ~（-3）~ 18.9 × 10 ~（-3），籽粒的平均DELTA值为16.4 × 10 ~（-3）~ 13.4 × 10 ~（-3）。当在单一环境中进行跟踪时，DELTA的值从c下降。早生叶20 × 10 ~（-3），籽粒15.4 × 10 ~（-3）。不同植株部位的DELTA基因型间变异均显著，典型的变异类型为c。2x10（-3）。在澳大利亚小麦中，DELTA的低值（意味着更大的蒸腾效率）与WW 15的遗传背景密切相关。DELTA的广义遗传力的估计平均超过95%，在基因型平均值的基础上，在实验中常见的基因型在许多环境中生长。在个别试验中，开花期附近取样的植物材料的遗传力最低（h2-DELTA（M）的平均值为83%，h2-DELTA（p）的平均值为62%），而在茎伸长早期之前或期间沉积的干物质的遗传力最大（h2-DELTA（M）的平均值为95%，h2-DELTA（p）的平均值为88%）。尽管谷粒DELTA的遗传力也相对较高（h2-DELTA（M）平均值为92%，h2-DELTA（p）平均值为79%），但由于在灌浆期间遇到的水分胁迫程度的基因型之间的差异导致DELTA的基因型排序的某些变化的可能性，难以解释谷粒DELTA的基因型差异。此外，再活化碳对谷物DELTA的贡献可能因环境和基因型而异。我们的结论是，对于小麦，在三角洲的基因型变异的评估应该是最有效的，在良好的浇水条件下，利用干物质奠定了植物发育的早期。
Carbon isotope discrimination (DELTA) has been proposed as a possible selection criterion for greater water use efficiency in breeding programs for water-limited environments because it provides an integrative assessment of genotypic variation in leaf transpiration efficiency. Considerable genotypic variation for DELTA has been demonstrated in wheat, but environmental factors may cause even larger changes in the value of DELTA measured in plant dry matter, which could compromise the effective use of DELTA in breeding programs. In this study we assess broad-sense heritability of DELTA and the significance of genotype x environment interaction for DELTA in field-grown wheat. Another objective was to identify the most effective growth stage or plant part to characterize genotypic variation in DELTA.Experiments were done using several large sets of genotypes (between 8 and 40, usually c. 20) grown in a range of field environments spanning the southern Australian wheat-belt. Carbon isotope discrimination was determined ou unreplicated grain samples from seven Interstate Wheat Variety trials grown in 1983 and 1984 and on several plant parts taken from replicated experiments conducted at four locations in south-west New South Wales from 1985 to 1988. From these replicated experiments broad-sense heritabilities for DELTA were calculated on a genotype mean basis (h2-DELTA(M)) and on a single-plot basis (h2-DELTA(p)).In dry matter sampled from several environments, site-mean DELTA ranged from 21.0X10(-3) to 18.9X10(-3) for early-formed dry matter and from 16.4x10(-3) to 13.4x10(-3) for grain. When followed in a single environment, the value of DELTA fell from c. 20x10(-3) in early-formed leaves to 15.4x10(-3) in the grain. Variation among genotypes in DELTA of different plant parts was always significant, and was typically c. 2x10(-3). Among Australian wheats, low values of DELTA (implying greater transpiration efficiency) were strongly associated with the WW15 genetic background.Estimates of broad-sense heritability for DELTA averaged over 95%, on a genotype mean basis, in experiments where common genotypes were grown in numerous environments. ln individual trials, heritability was lowest for plant material sampled near anthesis (average value for h2-DELTA(M), 83% and for h2-DELTA(p), 62%) and greatest for dry matter laid down before or during early stem elongation (average value for h2-DELTA(M), 95% and for h2-DELTA(p) 88%). Even though heritability for grain DELTA was also relatively high (average value for h2-DELTA(M), 92% and for h2-DELTA(p), 79%), genotypic differences in grain DELTA are difficult to interpret because of the likelihood of some changes in genotype ranking for DELTA resulting from differences among genotypes in the degree of water stress encountered during grain filling. As well, the contribution of remobilized carbon to grain DELTA may vary between environments and genotypes. We conclude that, for wheat, assessment of genotypic variation in DELTA should be most effective under well-watered conditions using dry matter laid down early in plant development.