| Lablab purpureus (L.) Sweet is an ancient legume species, commonly kown as lablab, who serves as vegetable, foodstuff and herb. Lablab has many outstanding qualities. In China, lablab serves as vegetable and Chinese medicinal herb. In recent years, the market demand for output and market quality in lablab gradually has exceeded the supply. In addition, lablab breeding obviously lags behind other legume plants in the world. It is needed to improve the output and market quality. Through years'observation of the inflorescence and fruit development in cultivated lablab varieties, we found that the florescence traits were significantly associated with output of lablab, fruit traits were the important factors of market quality in lablab and the growth phenological traits had influence on output and market quality of lablab to a certain degree.The objective of this study was to identify quantitative trait loci (QTLs) associated with the agronomic traits: floral axis rachis length, inflorescence length, peduncle from axis to axillae, peduncle from axillae to first flower, peduncle between extreme flowers, node number of inflorescence, rachis internode length, node of the first inflorescence, node of lowest florescence, pod length, pod diameter, pod flesh thickness, pod area, pod volume, flowering time, podding time and harvest maturity period in lablab, which were key factors of the output and market quality in lablab. And it was to observe the regulation of inflorescence differentiation, growth and development of florescence in lablab.A molecular linkage map was constructed by using 136 F2 progeny derived from a cross of'Medou 2012'×'Nanhui 23'. The map included 131 loci (122 RAPD and nine morphological loci), and the fourteen linkage groups covered 1302.4 cM with the average marker interval of 9.9 cM. Using the F2 population and F3 derived lines with composite interval mapping method, a total of 49 QTLs were detected on ten linkage groups for nine agronomic traits (floral axis rachis length, inflorescence length, peduncle from axis to axillae, peduncle from axillae to first flower, peduncle between extreme flowers, node number of inflorescence, rachis internode length, node of the first inflorescence, node of lowest florescence). Some QTLs were detectable in the same linkage regions among different generation/season combinations, suggesting genes which control inflorescence development were pleiotropic or coincident involving more than one trait. Thus these QTLs can be tagged for marker assisted selection in breeding high yield vegetable cultivars of lablab.Using 136 F2 population derived from a cross of'Medou 2012'×'Nanhui 23', the six agronomic traits, namely pod length, pod diameter, pod flesh thickness, flowering time, podding time and harvest maturity period were measured. Bayesian model selection was used to locate interacting QTLs for these traits. A total of 21 main-effect QTLs and 22 pairs of epistatic interactions were detected under that the threshold of statistic 2lnBF was 2.1 for declaring significance. The phenotypic variance explained by these QTLs ranged from 2.8% to 9.6%. In addition, we repeatedly measured eight agronomic traits, including five fruit traits (pod length, pod diameter, pod flesh thickness, pod area and pod volume ) and three growth phenological traits (flowering time, podding time and harvest maturity period) in F3 lines from two planting years in order to map the QTLs for these traits in lablab. Bayesian model selection was used to analyze main-effect QTL, epistatic QTL and main-effect QTL by environment interaction as well. As a result, a total of 30 main-effect QTLs were identified on 9 linkage groups with relative small phenotypic variances, and of which, 13 main-effect QTLs had interacted with two planting years. Twenty four pairs of epistatic QTLs were also found which accounted for large proportions of the phenotypic variations. In both F2 population and F3 lines, Some QTL and QEs were found to be pleiotropy. Two QTLs in F2 population, four QTLs and two QEs in F3 lines were pleiotropic. Among these QTLs, two QTLs were detectable among three generations, one responsible for flowering time, podding time and harvest maturity period, and another for flowering time and harvest maturity period simultaneously. These QTL were useful in MAS to improve the output and market quality of lablab.In order to probe into the regulation of growth and development of florescence in lablab, the inflorescence differentiation in the way of paraffin-cut section was observed with'Nanhui 23'and'Meidou 2012'as materials. Results showed that the process of inflorescence differentiation in lablab was from first-leaf time to four-leaf time, and could be divided into nine stages: unifferentiation phase, inflorescence differentiation elementary period, iInflorescence differentiation phase, single flower differentiation phase, bract differentiation phase, petal differentiation phase, stamen differentiation phase, pistil differentiation phase, inflorescence protraction phase. In the course of the whole inflorescence differentiation, the diameter of floral axis rachis in'Nanhui 23'was larger than that in'Meidou 2012', while the length of floral axis rachis in'Nanhui23'was less than that in'Meidou2012'. And in the development of floral axis rachis, there was the distinct difference in two accessions, and the development of floral axis rachis in'Nanhui 23'was two day long than that in'Meidou 2012'. In addition, the developments of all traits about floral axis rachis were evidently influenced by environment.
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