中国糯玉米wx基因种质资源遗传多样性

Waxy(Wx)基因是众多作物导致糯性突变的关键基因，在玉米作物群体内深入研究Wx基因对中国糯玉米品质育种和种质创新具有重要意义。本研究利用325份(309份来自中国，11份来自泰国和5份来自韩国)糯玉米种质材料做了wx基因突变类型的调查和表观直链淀粉含量(AAC)测定。结果表明, 中国糯玉米的wx基因的遗传多样性很低，主要存在wx-D7和wx-D10两种突变类型，占96.9%；中国北方及韩国的糯玉米wx基因突变类型都是wx-D7类型，南方及泰国糯玉米wx基因突变类型都是wx-D10类型；糯玉米地方品种的wx基因型以wx-D10为主，占78.9%，而商业杂交种和自交系的wx基因型以wx-D7为主，分别占88.7%和86.6%。分析表明，中国糯玉米商业杂交种和自交系的AAC均值较低(小于2.2%)且无显著差异，但地方品种的AAC均值较高；wx-D7基因型糯玉米的AAC均值低且变化幅度较小，而wx-D10基因型糯玉米的AAC均值最高且变化幅度较大。本文还讨论了中国糯玉米主要wx基因型的地理分布、起源以及其他的wx基因突变类型。

Genetic Diversity of Waxy Gene in Chinese Glutinous Maize

Waxy (Wx) gene is the key gene for glutinous trait in many waxy crops including waxy maize. Wx diversity investigation in maize population has important significance for quality breeding and germplasm utility of Chinese waxy maize. In this study, 325 waxy maize germplasm accessions (309 from China, 11 from Thailand and five from South Korea) were used to investigate their wx genotypes and determine their apparent amylose content (AAC). Our results demonstrated that genetic diversity of wx gene in Chinese waxy maize was low, and two mutation types, wx-D7 andwx-D10, account for 96.9% of the 325 accessions. Among these accessions, those from North of China and South Korea were the type of wx-D7 while others from South of China and Thailand were the type of wx-D10; most of landraces were the type of wx-D10 (78.9%) while most commercial hybrids and inbred lines were the type of wx-D7 (88.7% and 86.6%, respectively). AAC estimations indicated that mean values of AAC in commercial hybrids and inbred lines in China were lower than 2.2% while that in landraces was relatively high. Comparing with wx-D7, wx-D10 waxy corn had higher AAC with larger changing range. Geographical distribution and origins of two main wx genotypes and other wx genotypes were discussed also.