| The 15 hybrid combinations made by using 6 hexaploid Triticale cultivars as parents according to complete diallel cross were planted adopting randomized block experiment in the experimental station of agricultural college in Shihezi University in 2006 in order to investigate the genetic rule of mainly economic traits. The genetic effects, heritability, heterosis and genetic correlation by additive-dominant model as well as combining ability and canonical correlation by DPS software of 7 yield traits (i.e. grain yield per plant, Number of spikes per plant ,kernels per spike, 1000-grain weight, plant length, internodes length below spike and length of spike) and 5 forage quality traits (i.e. crude protein content, crude ash, crude fat, crude fiber and nitrogen-free extract) were analysed. The main results were as follows:1. the analysis of genetic effects of yield traits in Triticale show that 1000-grain weight and internodes length below spike were controlled by both additive effect and dominant effect, and plant height was mainly controlled by additive gene actions, whereas grain yield per plant and kernels per spike were controlled not only by additive and dominant effects but also by epistasis and environment effects and length of spike was controlled by no-additive effect; the analysis of genetic effects of forage quality traits in Triticale show that crude protein content was controlled by additive and no-additive effects, and crude fat, crude fiber and nitrogen-free extract were controlled by dominant effects, whereas crude ash was controlled additive and dominant effects. In addition, dominant effects of per parent showed that the most traits had obvious selfing depression.2. Heritabilities of different yield traits had remarkable difference. Heritability of plant length and internodes length below spike were relatively high, the second were kernels per spike and 1000-grain weight, whereas grain yield per plant and length of spike were relatively low. The heritabilities of forage quality traits were all relatively low.3. Most traits of hybrid combination in Triticale had remarkable heterosis. Except kernels per spike, other traits of F1 had remarkable positive heterosis of population means, whereas heterosis of population means of grain yield per plant were the highest. Crude fat and crude fiber had positive heterosis of population means, and nitrogen-free extract had negative heterosis of population means, whereas the others weren't clear in forage quality traits of F1. Heterosis of population means of F2 were similar to that of F1, whereas the heterosis value of F2 was about 50% lower than that of F1. The most traits of F1 and F2 had clearly population heterobeltiosis. The heterosis of grain yield per plant, crude fat and crude fiber could reach into F2, and the stronger heterosis could reach into F3.4. The analysis of genetic correlation among yield traits revealed that correlations among phenotype and correlations among genotype were similar. Grain yield per plant positively and significantly correlated with kernels per spike in the additive correlation, grain yield per plant and plant length, grain yield per plant and internodes length below spike were negative and significant in the additive correlation. Crude protein content and crude ash were positive and significant in the additive and dominant correlation.5. Except internodes length below spike, variance of combining ability of yield traits and forage quality traits were highly significant. XIN Triticale No.5 was better parent for yield breeding and XIN Triticale No.1 and XIN Triticale No.5 were better parents for forage quality traits. XIN Triticale No.5×H03-7 and XIN Triticale No.1×XIN Triticale No.4 were a hybrid combination for increasing yield potential. XIN Triticale No.1×XIN Triticale No.3 and 04CaoJian3×XIN Triticale No.4 were good combinations for improving forage quality traits. 6. Grain yield per plant, plant length and internodes length below spike were canonical variable among yield traits and yield traits in Triticale; grain yield per plant, crude ash and crude fat were canonical variable among yield traits and forage quality traits in Triticale.
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