Department of Plant and Soil Sciences, Mississippi State University, 117 Dorman Hall, Box 9555, MS 39762, USA.
Toxins (Basel). 2013 Jan 15;5(1):162-72. doi: 10.3390/toxins5010162.
Maize breeders continue to seek new sources of aflatoxin resistance, but most lines identified as resistance sources are late maturing. The vast difference in flowering time makes it hard to cross these lines with proprietary commercial lines that mature much earlier and often subjects the reproductive phase of these resistant lines to the hottest and driest portion of the summer, making silking, pollination and grain fill challenging. Two hundred crosses from the GEM Project were screened for aflatoxin accumulation at Mississippi State in 2008, and a subset of these lines were screened again in 2009. The breeding cross UR13085:S99g99u was identified as a potential source of aflatoxin resistance, and maturity-based selections were made from an S2 breeding population from this same germplasm source: UR13085:S99g99u-B-B. The earliest maturing selections performed poorly for aflatoxin accumulation, but later maturing selections were identified with favorable levels of aflatoxin accumulation. These selections, while designated as "late" within this study, matured earlier than most aflatoxin resistant lines presently available to breeders. Two selections from this study, designated S5_L7 and S5_L8, are potential sources of aflatoxin resistance and will be advanced for line development and additional aflatoxin screening over more site years and environments.
玉米育种者继续寻找新的黄曲霉毒素抗性来源，但大多数被鉴定为抗性来源的品系成熟较晚。开花时间的巨大差异使得这些品系很难与成熟时间早得多的专有商业品系杂交，而且往往使这些抗性品系的繁殖阶段处于夏季最热、最干燥的时期，使花丝、授粉和灌浆变得具有挑战性。2008 年，GEM 项目的 200 个杂交种在密西西比州立大学进行了黄曲霉毒素积累筛选，其中一部分品系在 2009 年再次进行了筛选。UR13085：S99g99u 被鉴定为黄曲霉毒素抗性的潜在来源，并且从同一种质来源的 S2 育种群体中进行了基于成熟度的选择：UR13085：S99g99u-B-B。最早成熟的选择在黄曲霉毒素积累方面表现不佳，但后来成熟的选择具有有利的黄曲霉毒素积累水平。这些选择虽然在本研究中被指定为“晚期”，但比目前育种者可用的大多数黄曲霉毒素抗性品系成熟更早。本研究中的两个选择，S5_L7 和 S5_L8，是黄曲霉毒素抗性的潜在来源，将在更多的地点和环境中进行线路开发和进一步的黄曲霉毒素筛选。
