Study Of Combining Ability And Heterosis For Major Characters Of Leafy Maize

Maize is one of the main crops, which plays an important role in the national economic development. For a long time, lacking of germplasm resources was the leading problem of the maize breeding in our country. The fast development of livestock has a big demand on embodied germplasms of forage maize,which were deficient especially, So it is necessary to add new germplasm and expand use of germplasm resources.Leafy maize material is a new-type of germplasm derived from U.S.A, leafy maize had 8-25 leaves above the ear, and better stalk strength much taller than non-leafy maize and more flourishing root, their stem stalk was stalwart, their resistance was strong synthetically. This study was conducted by 6 inbred lines and 75 hybrid as materials which were from incomplete diallel cross of 6 groups of leafy maize (According to different leaf numbers above the ear, inbred lines were divided into 8 leaves, 9 leaves, 10 leaves, 11 leaves, 12 leaves). Analyses were made for the combining ability, average heterosis and correlaton of the main characters of leafy maize. The results were as follows:(1)The difference among parents and FI was very remarkable . It indicated that leafy character was controlled by the hereditary of the genotypes.(2)Analysis of GCA effect showed that the difference of combining ability effect value existed in different leaves of the same characters, or different characters of the same combination . Hereditary character of GCA effect had difference in different leaves above the ear, it indicated that combining ability should be evaluated according the different leafy group. In this study, the inbred line Y53 of 11 leaves above the ear showed good effect relatively at agricultural characters, quality characters and yield. Similarly, the inbred line P175, with 12 leaves above the ear, showed better, but different leaves of inbred lines P19, P85 , J7-3 and M7, whose effectswere negative mostly, this showed the generation crossed by them can be weakened on each character.(3)Through relativity analysis of the main characters of 75 combinations ,we can know, the relativity of each character in different leaves was different. Except for 12 leaves , in 8, 9, 10,11 and 12 leaves of combinatins above the ear,, the relativity of plant-height and biological yield, ear-height and biological yield was high, there was not remarkable relativity between other characters and biological yield. In 8 leaves above the ear, relativities of height, biological yield and crude starch were much strong; In 10 leaves, there was extremely remarkable relativity between crude starch , crude fibre and ear-height; In 11 leaves, plant-height and crude fibre, 100-grain weight and crude starch showed extremely remarkable; In 12 leaves, there was positively relevant between 100-grain weight and crude fibre; Those indicated that inbred lines of 8, 9, 10 and 11 leaves above the ear had the potentiality on cultivating silage maize.(4) 6-leafy maize series,with different hereditary background of maize,were used by the study of their combining ability and heterosis,we obtained 53*PI75 above the 11 leaves of ear,which had high-yield, high-quality characters elementarily. This combination can be used as a new variety of silage maize,it could also promote livestock to develop better and faster .