“三步选择”法在优质多抗鲜食玉米品种选育中的应用

Application of’Three-step Selection’Method in Breeding of High-quality and Multi Resistant Fresh Corn Varieties

鲜食玉米因其兼具粮、果、蔬三类食物特性,具有巨大的市场消费潜力。但其育种过程中由于自交系品质、抗性、配合力不能协调统一,选育品种综合优势不突出,无法满足市场的需求。本研究提出采用大群体逆境胁迫选择、半穗品鉴半穗留种法和配合力测试相结合的“三步选择”方法选育优质、抗逆、高配合力鲜食玉米自交系。第一步选择优良基础种质,在其基因分离世代进行大群体逆境胁迫高压种植,选择抗逆性好的植株套袋自交。第二步在当选植株中通过半穗品鉴半穗留种法选择品质好的果穗留种,果穗老熟后于下一代种成穗行。第三步进行配合力测试,采用测配结合,边测配边组配的方法,测定新选系的配合力和组配新组合同时进行。通过该方法选育出优良自交系16个,组配甜玉米品种9个和糯玉米品种9个。实践表明该育种方法简化了鲜食玉米育种程序,提高了优良自交系的选择效率和优良品种组配成功率,为优质、抗逆、高配合力鲜食玉米新品种选育指明了方向。

Fresh corn has the characteristics of grain,fruit and vegetable,and has great market consumption potential.However,the high-quality,resistance and combining ability of inbred lines can’t be coordinated and unified in the breeding process,and the comprehensive advantages of the selected varieties are not prominent,which can’t meet the needs of the market.We here proposed a three-step selection breeding method for fresh corn,which combined multiple adversity stresses selection on large-population size,half-sibling for taste-evaluation and half-sibling seeds for successive combining ability test breeding from a same ear.This method significantly improves the breeding efficiency of fresh corn inbred lines with high quality,stress resistance and high combining ability.The first step is starting from elite basic germplasm,and carrying out strict adversity stress selection based on large-population size at genetic segregation phases,and then obtaining ideal individuals after selfing.In the second step,another sibling half from better taste-evaluating sibling is reserved for further breeding steps.The third step is to carry out the combining ability test,in which the combining ability of newly selected lines are tested and potential hybrid combinations are simultaneously made.Using this strategy,16 elite inbred lines,9 sweet corn varieties and 9 waxy corn varieties had been bred.Our breeding practices showed that this method can simplify the fresh corn breeding program,and improve efficiencies of both elite inbred line selection and elite hybrid variety breeding.All these will point out a direction for the breeding of new fresh corn varieties with high quality,stress resistance and high combining ability.