| Seed is the base of summer squash production and new variety breeding, but also the key of studying on seed with summer squash variety. In order to carry out genetic analysis of squash seed traits, explore the correlation between seed and fruit shape of long fruit summer squash(fruit shape index>2.5), optimize summer squash breeding technology, the experiment selected two summer squash inbred lines S-16(?), 08-5(?), which are highly different in seed and fruit traits were used to build the six generation groups(P1, P2, F1, BCP1, BCP2, F2);Using plant quantitative traits majorgene+polygene mixed genetic model carried out genetic analysis on the squash seed phenotypic traits; Using the completely random design of experiment and linear regression analysis method analyzed the correlation between seed traits and fruit traits with eight inbred lines; Using L9(33) orthogonal experiment design analyzed the effects of seed production technology such as pollinating times, fruit setting node and fruit age on seed yield and quality with summer squash inbred line of 08-5.The results showed that:1. The genetic model of summer squash seed length was additive+dominant+epistatic model with two pairs of major genes(B-1).Genetic effect was given priority to with dominant+ dominant+epistatic effect.The major gene heritability of separating generation of BCP1, BCP2 and F2 were 99%, 46.17% and 24.03%, BCP1 was mainly influenced by major genes, less affected by the environment, suitable for selecting in early generation; BCP2 and F2 were greatly influenced by the environment, suitable for selecting with individual selection method in high generation. The genetic model of summer squash seed width was additive+dominant+epistatic model with two pairs of major genes and additive+dominant model with polygenes(E-1).There was heterosis in F1 and genetic effect was given priority to with additive effect of polygenes. The major genes heritability of separating generation of BCP1, BCP2 and F2 were 1.05%, 89.01%, 85.32%. BCP1 was mainly controlled by major genes, polygenes heritability were 98.48%, 0%, 0%. Differences between separating generation is mainly caused by major and polygenes, less affected by the environment and suitable for selection in the early generation.The genetic model of summer squash seed shape index was E-1. Genetic effect was given priority to with dominant+ dominant+epistatic effect.The major genes heritability of separating generation of BCP1, BCP2 and F2 were 81.86%?89.88%? 81.33%. less affected by the environment and suitable for selection in the early generation.2. Long fruit summer squash seed length, width and shape index respectively with fruit vertical diameter? horizontal diameter and shape index had significant positive correlation relationship. The correlation index between seed length and fruit vertical diameter was0.8165 >r0.05. The correlation index between seed width and fruit horizontal diameter was0.7547 >r0.05. The correlation index between seed index and fruit index was 0.7093 >r0.05, all reached significant level. There was a significant positive correlation relationship between long fruit summer squash seed shape and fruit shape, The fruit shape can be inferred by seed shape.3. Pollinating times had highly significant effects on seed number per fruit(p<0.01),significant effects on 100-seed weight and seed yield per fruit(p<0.05), but no significant effects on four seed quality indicators(p>0.05). Fruit setting node had significant effects on100-seed weight, seed yield per fruit, germination potential, germination index and vigor index, no significant effects on seed number per fruit and germination rate. Fruit age had highly significant effects on 100-seed weight, seed yield per fruit, germination index and vigor index, significant effects on germination potential, but no significant effects on seed number per fruit and germination rate. In conclusion, the best treatment was P2N1T3:pollinating twice, fruit setting at the second female flower node and for 45 days. |
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