Evaluation Of Ornamental Tomato Germplasm Resources And Analysis Of Genetic Effects Of Hybrid Generation

From the current development of tourism agriculture,the lack of ornamental tomato varieties with independent property rights has become an important factor restricting the development of ornamental tomato.At present,there are few reports on the collection,evaluation and further utilization of ornamental tomato germplasm resources.In this paper,genetic diversity analysis,trait correlation analysis,principal component analysis,cluster analysis and analytic hierarchy process analysis were carried out for each agronomic character of 26 ornamental tomato germplasm resources collected by the research group,so as to realize the evaluation and analysis of ornamental tomato germplasm resources.By referring to the evaluation results of 26ornamental tomato germplasm resources mentioned above,7 germplasm resources with good ornamental properties,good characters and strong disease resistance were selected as parents for hybridization,the heterosis and combining ability of parents in F₁ generation were analyzed,and the excellent parents and hybrid combinations were selected.The results show that:1.Analysis and evaluation of 26 ornamental tomato germplasm resourcesThe variation coefficients of all quantitative traits ranged from 0.09-0.99.The diversity index of quality traits was distributed between 0.16 and 1.63,and there was no separation of traits among the cultivars of pedicel separation layer.Fruit color and fruit shape phenotype are relatively diverse,and the diversity index is the highest.The correlation analysis of traits showed that there was a significant positive correlation between phenological traits and inflorescence traits.In terms of plant morphology,fruiting stage was positively correlated with plant height and stem diameter,while inflorescence and fruit size were positively correlated with plant morphology.In terms of strain-forming traits,there was an extremely significant positive correlation among the three traits of single inflorescence flower number,single inflorescence fruit number and single inflorescence length.In terms of fruit traits,there was a significant positive correlation among fruit weight,cross diameter and longitudinal diameter.Principal component analysis showed that the cumulative contribution rate of the first four principal components was 82.259%,which could reflect most of the information of 20 traits,including the whole plant shape factor,fruit and cluster factor,phenological phase factor,fruit color factor and other aspects of ornamental tomato traits.Through cluster analysis with Ward’s method,the 26 ornamental tomato germplasm resources were divided into three subgroups with an Euclidean distance of about 10,namely,dwarf and small fruit subgroup,tall and large number of fruits and flowers subgroup and dwarf and big fruit subgroup.The analytic hierarchy processshowed that the constraint layer of fruit shape features accounted for the largest weight in the constraint layer,and the fruit color index layer accounted for the largest weight in the index layer.The final score and classification results showed thatthe numbered S1 germplasm shows the germplasm material numbered S1 has the highest ornamental value and belonged to the varieties with high application value.2.Heterosis analysis of hybrid generationHybrid F1 heterosis analysis results show that the equipping of 21 hybrid combinations,the early maturity traits,except♀P3×♂P4 were negative in themid-parent heterosis,super-parentheterosis and early maturity phenotype is obvious;Fruitsetting period,♀P2×♂P7showed the positive mid-parent heterosis and the rest of the hybrid combinations showed negative in themid-parent heterosis and super-parent heterosis,same as the beginning of flowering performance trend of heterosis;The heterosis of the first inflorescence segment was different in different combinations,even in the hybrid combinations of the same parents.In terms of plant morphology,plant height,stem diameter,maximum leaf length and maximum leaf width were mostly between two parents,and slightly inclined to low-value parents.The number of lateral branches in each combination showed strong positive heterosis.In terms of a series of traits,the single inflorescence length and the single inflorescence number of different combinations showed strong negative heterosis,and the performance of hybrid combinations was biased towards low-value parents;among the single inflorescence fruit traits,15 of 21 combinations showed strong positive heterosis.3.Combining ability analysisEach parent exhibited a different general combining ability in different traits.Among them,the parent P5 is suitable for the preparation of early-maturing ornamental tomato combination;the parentsP1 and P7 are suitable for the preparation of the dwarf ornamental tomato hybrid combination;the parent P3 is suitable as the parent of the planting plant hybrid tall and leafy ornamental tomato hybrid combination;the parent P6 is suitable for the overall viewing good ornamental tomato hybrid combination.In summary,the parents P3,P5 and P6 not only showed high general combining ability,but also could formulate hybrid combinations with high special combining ability.The comprehensive traits were excellent and the breeding potential was huge,which could be selected as the follow-up breeding material;♀P2×♂P5 is the best combination of selected F₁ generations of ornamental tomato hybrids,which can be further utilized as excellent hybrids.♀P3×♂P6 and♀P5×♂P6 can be used as excellent combinations for cultivating new ornamental tomato varieties.