Experimental evaluation of the potential of tropical germplasm for temperate maize improvement
Experimental evaluation of the potential of tropical germplasm for temperate maize improvement
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DOI：
10.1007/s001220051039
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发表时间：
1999-01
影响因子：
5.4
通讯作者：
S. Tallury;M. Goodman
中科院分区：
文献类型：
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作者：
S. Tallury;M. Goodman
商品玉米（Zea maysL.）在美国，具有有限的遗传基础，因为较新的杂交种主要是由代表硬茎和兰开斯特遗传背景的小样本（主要是约6至8个碱基的近交系）的优良近交系之间的杂交产生的。因此，玉米遗传多样性的扩大一直是育种者面临的一个持续挑战。热带种质被认为是一个有用的多样性来源，虽然热带种质整合到现有的自交系和杂交开发是费力的。本研究旨在评价热带种质在温带玉米改良中的潜力。所有可能的单，三路，和双杂交三大温带和三个温度适应，全热带自交系进行了评估，在产量试验测试。热带种质含量达50-60%的单交种，产量为8.0t/ha，相当于商品对照种的平均产量。 另一方面，具有最高平均产量的三交和双交杂种包含较低数量的热带种质，分别为10-19%和34- 44%。总的来说，含有10-60%热带种质的杂交种在商业杂交种检查的范围内产生。热带种质含量超过60%的杂交种产量显著降低，100%热带种质的杂交种产量最低。结果表明，热带种质自交系不仅是扩大玉米杂交种遗传多样性的有效来源，而且在与温带材料杂交中具有竞争力，可产生高产杂交种。这些试验杂交种表现出良好的站立性（与商业对照杂交种相当），但含有1-2%的高籽粒水分，导致延迟成熟。正在对这些材料的衍生物进行循环选择程序，以提取具有上级产量、良好的站立性和降低的谷物水分的品系，这些品系可用于商业开发。
Commercial maize (Zea maysL.) in the USA has a restricted genetic base as newer hybrids are largely produced from crosses among elite inbred lines representing a small sample (predominantly about 6- to 8-base inbreds) of the Stiff stalk and Lancaster genetic backgrounds. Thus, expansion of genetic diversity in maize has been a continuous challenge to breeders. Tropical germplasm has been viewed as a useable source of diversity, although the integration of tropical germplasm into existing inbred line and hybrid development is laborious. The present study is an evaluation of the potential of tropical germplasm for temperate maize improvement. All possible single-, three-way-, and double-cross hybrids among three largely temperate and three temperate-adapted, all-tropical inbred lines were evaluated in yield-trial tests. Single-cross hybrids containing as much as 50–60% tropical germplasm produced 8.0 t ha-1of grain yield, equivalent to the mean yield of the commercial check hybrids. On the other hand, three-way and double-cross hybrids with the highest mean yield contained lower amounts of tropical germplasm, 10–19% and 34–44%, respectively. Overall, hybrids containing 10–60% tropical germplasm yielded within the range of the commercial hybrid checks. Hybrids with more than 60% tropical germplasm had significantly lower yields, and 100% tropical hybrids yielded the least among all hybrids evaluated. The results indicate that inbred lines containing tropical germplasm are not only a useful source to expand the genetic diversity of commercial maize hybrids, but they, also are competitive in crosses with temperate materials, producing high-yielding hybrids. These experimental hybrids exhibited good standability (comparable to the commercial check hybrids) but contained 1–2% higher grain moisture, leading to delayed maturity. Recurrent selection procedures are being conducted on derivatives of these materials to extract lines with superior yield, good standability, and reduced grain moisture which can be used for commercial exploitation.