Preliminary Studies On Improvement And Application Of Some CIMMYT Populations

Introgression and application of exotic germplasm is a key way to solve the straitness of genetic background in corn breeding in China. Most tropical and subtropical germplasm from CIMMYT is difficult to apply directly in Heilongjiang province. It is necessary to improve them with the temperate germplasm. A NCII test design was adopted to cross 6 common temperate testers in China with 4 Populations from CIMMYT to analyze combining ability(GCA and SCA)and heterosis to conduct the further improvement and application of CIMMYT germplasm. On the other hand,means,character parameters,combining ability (GCA and SCA) and heterosis were analyzed on extra-early CIMMYT Population Pob101 after four cycles mass recurrent selection to estimate the effect of improvement. The main results are summarized as follows:1.The preliminary praisal and principal component analysis of four CIMMYT Populations showed that:they were later-maturity, higher plant height,bigger biology product and better expression of green keeping in commen,and were difficult to apply directly in Heilongjiang province2.Studies on Combining ability and heterosis among five populations from CIMMYT and domestic testers showed the headling of further improvement for the populations:(1)Pob45 crossed with B73 demonstrated the lowest SCA among the 6 crosses with 6 testers and the lowest herterosis except being crossed with Qi319 so Pob45 could be used to improve Reid germplasm represented by B73.(2)Pob46 crossed with Mo17 had the lowest SCA among the 6 crosses with 6 testers,and the herterosis was also the lowest except being crossed with Qi319, so it could be used to introduce to Lancaster germplasm represented by Mo17.(3)Pob69 had the nearest genetic relationship with Ye107 among 6 testers,so it might be introduced to PA germplasm represented by Ye107.(4)The lowest SCA of Pob70 with the 6 testers was bing crossed Qi319;Dan340 is subordinate lower,so Pob70 could be introduced into Qi319 for silage corn breeding,it might be intrduce to Lvdahonggu germplasm represented by Dan340,and could be used to bord the resource for common corn breeding.(5)Pob101×Ye478 demonstrated the lowest M-H and C-H, so Ye478 might be considerated to introduced to the Population.3.According to the analysis on combining ability ang heterosis,the headling of using these five populations could be:(1)Pob45 crossed with Mo17 demonstrated the highest SCA and herterosis among the 6...