In order to create compact waxy corn germplasms, Zheng58 (a compact common maize inbred line) and Tong759 (a expanded waxy maize line) were used as donor and recurrent parent, respectively. The favorable alleles of major QTL (qLA5) for leaf angle were transferred by backcross with seletion for leaf angle combined marker-assisted selection and 29 plants for BC2F2 were created. Through the background selection of 48 markers and the comprehensive identification of 18 traits such as plant type, stress resistance, yield and quality under high density, 4 new waxy germplasms with compact plant type, high yield, strong stress resistance and good quality were screened out. The average genomic content of the recurrent parent in 4 new germplasms increased from 78.48% to 88.67%, which can be used as parent materials for compact waxy maize breeding. The results of this study provide theoretical references for the improvement of waxy maize germplasms by using common maize and the breeding of new compact and high quality fresh eating waxy maize varieties.
In order to compare the differences of different clones of diploid and tetraploid Robinia pseudoacacia tissue culture plantlets, the morphological and physiological indexes of the diploid and artificially induced tetraploid tissue culture plantlets of Robinia pseudoacacia were determined and analyzed. The results showed that the growth and stress resistance of most tetraploid Robinia pseudoacacia clones were better than that of diploid clones; there were abundant variations between and with diploid and tetraploid Robinia pseudoacacia clones in different morphological and physiological indices, but the variation of tetraploid Robinia pseudoacacia was more abundant; there were complex correlations among the tested indices. Comprehensive consideration should be taken in selection and breeding. According to the results of the experiment and the breeding objectives, the excellent tetraploid Robinia pseudoacacia clones can be selected to enrich the germplasm resources of Robinia pseudoacacia and increase its genetic diversity.