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Studies on Leaf Abscission at Maturity and Agronomic Characters in Adzuki Bean
|關鍵字:||Adzuki bean;紅豆;Leaf abscission;Germplasm;Leaf abscission genotype;F2 population;落葉性;種原;落葉型;F2族群||出版社:||農藝學系||摘要:||
The main purposes of this research are to investigate the variation of leaf abscission at maturation stage and the other agronomic characters in 332 germplasms, 12 varieties of three leaf abscission genotypes, and F2 population of 7 cross combinations for adzuki bean, in order to select cross parent and develop selection. The results were summarized as follows:
(a) Variation on leaf abscission at maturity and the other
agronomic characters in 332 germplasms of adzuki bean.
The variation of leaf abscission at maturation stage and the other agronomic characters are different significantly among adzuki bean germplasms from various regions. In generally, the variation potential of leaf abscission in Taiwan gerplasms are larger than in China's. It might be caused to the different breeding purposes in different regions. The results showed that there are only 7 varieties have completely fallen their leaves at maturation stage among 332 germplasms. The 7 varieties could be as good materials to improve the less leaf abscission at the maturation stage. According to the genetic analysis, it showed the leaf abscission at maturation stage has wide variation potential but lower heritability. In contrary, both of the plant height and hundred-grain weight have higher heritability. The relationship between leaf abscission percentage and plant height and hundred-grain weight are negative. The correlation analysis showed the genetic factors including plant height, plant weight, hundred-grain weight, branch number, pod number, grain size, and plumpness of grain are all benefits to the yield. On the other hand, the genotype with better of leaf abscission downgrade its production. According to the path analysis revealed the total plant weight and pod number per plant contributed the maximum yield. However, the percentage of leaf abscission was negative to the seed production.
(b) The relationship between the different growth stages and
seed production for 12 varieties of three leaf abscission
According to the timing of leaf abscission, delay leaf abscission (DLA), normal leaf abscission (NLA), and early leaf abscission (ELA) were discriminated. The accumulation of pod weight per plant is similar among three types of adzuki bean mentioned above no matter of developing stage in spring crop season except for two ELA varieties, CR and AD. However, it was affected by the timing of leaf abscission in NLA and ELA genotypes in fall crop season. Besides, DLA genotype has the highest pod yield per plant than the others in both crop seasons. It might bring about the higher of filling rate and the longer of filling period. Furthermore, the accumulation of pod weight per plant of ELS, a NLA variety, was decreased by lower of filling rate and shorter of filling period. On the other hand, its accumulation in two ELA varieties, RL64 and AD, was only resulted from lower of filling rate.
(c) Variation of leaf abscission at maturation stage and the
other agronomic characters in F2 population of 7 cross
According to the principal component analysis in F2 population of 7 cross combinations, there are three groups are classified. The group1 including four cross combinations, C191, C192, C193, and C194, and the group2 is composed to two combinations, C189 and C190. The analyzed results showed highly relationship in the same group. But, the group3 is only containing one combination, C188. It could cause to the farther genetic background than others. The percentage of leaf abscission (LAP) at maturation stage by distribution frequency analysis showed that all 7 cross combinations have transgressive segregation compared to their parents and trend to the continued distribution for right skewness. The heritability of LAP of 7 cross combinations are from 0.211 to 0.550. It prospected that this trait was controlled by at least 2 to 4 alleles and would be affected easier by environmental condition. The lower heritability suggests that it would be more benefit to select at later generation instead of earlier generation. The path analysis of production showed that total plant weight and pod numbers per plant are the main components of seed production. The direct effect of LAP at maturation stage showed positive correlation with seed production of all 7 combinations. However, the final relationship between LAP and seed yield of C190, C191, C193, and C194 combinations were negative, and C188, C189, and C192 combinations have no significantly correlation. They both result from the indirect negative effect of total plant weight to seed production. In conclusion, it's possible to select the genotype not only possesses good leaf abscission at maturation stage but also with higher seed production from C188, C189, and C192 combinations of segregation populations.
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