玉米材料的耐密性鉴定及耐密型育种的思考

逐步增加玉米种植密度是当前玉米生产发展的必然趋势,而玉米自交系的耐密性在一定程度上决定了杂交种的耐密性。以夏玉米育种上常用的4个基本骨干自交系为试验材料,以耐密自交系130为对照,在种植密度7.5万～15.0万株/hm^2范围内设计6个梯度水平,分析不同种植密度对玉米主要生育期、穗部性状、倒伏倒折率和产量的影响,旨为耐密型玉米育种提供合理的选系密度。结果表明：随着种植密度的增大,4个参试玉米材料的穗长变短、穗粗变细、秃尖长度增大,当密度超过某一个范围后倒伏倒折率明显增大,产量呈先增加后降低的变化趋势,其中产量最高的种植密度范围为12.0万～13.5万株/hm^2;而耐密自交系130（对照）的穗部性状变化幅度较小,倒伏倒折率明显较低,产量一直呈增加趋势。在试验密度范围内,不同种植密度对同一玉米材料的主要生育期和穗行数均无显著影响。并对耐密型玉米品种选育的种植密度和杂交种鉴定技术进行了探讨,认为在选择耐密型自交系时低代选系材料的种植密度应〉13.5万株/hm^2,在选择耐密型杂交种时还要保证穗粒数和穗粒重不能降低得太多,对耐密型杂交种进行鉴定时设立一年多点异地鉴定并适当加大鉴定种植密度。

Thinking of the High Density Tolerance Identification and Breeding for High Density Tolerance of Maize Materials

Gradually increase maize planting density is the inevitable trend of the development of maize production,while the high density tolerance of maize inbred lines to a certain extent determines the high density tolerance of hybrids.With 4 commonly used basic inbred lines in the breeding of summer maize as experimental materials,the resistant inbred line 130 as the control, and 6 density levels was designed during the planting density of 75 000-150 000 strains / hm^2,the effects of planting density on the growth period,ear traits,lodging percentage and yield of maize were analyzed to provide reasonable density for the breeding of high density tolerance of maize.The results showed that with the increasing of planting density,the spike length of 4 tested maize were shortened,spike diameter were attenuated,bald tip length were increased,when the density exceed a certain range,the lodging rate were increased significantly,the yield showed a trend of first increase and then decrease,the highest yield planting density range was 120 000-135 000 strains / hm^2.The inbred line 130（ CK） panicle traits were changed slightly and lodging rate was decreased significantly, the yield has been increased.In the experimental density range,there were no significant effects on the growth stage and number of rows per ear of different planting densities of the same maize material.At the same time,planting density for breeding of density tolerance and the identification technology of hybrid were discussed,it considered that in the selection of highdensity tolerant inbred lines,planting density of low generation materials should be higher than 135 000 strains / hm^2,also ensured that the grain number and grain weight per spike could not be reduced too much in the selection of high density tolerant hybrids.When identification of hybrids of highdensity tolerance,we should set up more sites and remote,then increase the planting density properly.