Study On Breeding Value Of Virus Resistant Progenitors And Important Characters Of Their Tuber Family In Potato (Solanum Tuberosum. L)

Most of potato germplasm introduced from CIP adapted to the short day conditions and showed some undesirable characters under long day conditions in China. However, these germplasm have abundant genes and different genetic background from those in China. It will be helpful to improve the breeding germplasm and to breed new potato varieties by using these germplasm. Important information of these germplasm could be obtained after this study.The field experiments for the 1440 genetypes from 24 introduced crosses had been conducted for two years at two locations. The virus resistant, tuber yield, starch content, marketable tuber weight percentage, chipping color of these hybrid tuber families were evaluated under long day conditions. In the meanwhile, the interreaction between the potato genotypes of main traits and the environment, and the relationships between different traits were studied.13 crosses of C91.628×C93.154, C91.640×C93.154 etc.and 5 progenitors of C91.628, C91.640 etc.with high resistant to viruses and 10 crosses including C91.640×TXY.2, C91.612×TXY.2 etc. with high yield, high starch content and marketable tuber weight percentage were screened out for good breeding value.The results of the interreaction between genotype and environment indicated that the main factor causing the difference between phenotypes was the genetic difference between tuber families. Tuber size and tuber set were affected greatly by the environment. Tuber yield and chipping color were relatively stable in different environments. Without consideration of the interreaction between genotype and environment, it could be easy to make mistakes in evaluation of genotypes. It is very important to evaluate the same tuber family at different locations in potato breeding.The results of principal component analysis showed that the contribution importance to variance in order were commercial factors (including marketable tuber weight percentage, tuber size), yield factors (including tuber yield, tuber set), virus factors (including chipping color,PLRV influence percentage) , plant height factors and starch factors. After estimatefor the tuber set of good yield tuber families, the tuber size and marketable tuber weight percentage can be merged into yield factors in breeding. Only Tuber yield and tuber set could be evaluated while selecting in the field. The elite clones could be selected by the following steps: first, mark disease free progeny plants in the field, then select tuber yield and tuber set while harvesting, and finally test specific gravity and chipping color of tubers in the laboratory.1046 excellent clones were screened out for further evaluation in potato breeding program.