Identification And Heat-tolerance Preliminary Evaluation Of Lily Hybrids

Lily breeding of heat-tolerance is an important part of the lily breeding of resistance. Because of the problems of the self-incompatibility and cross-incompatibility in lily conventional breeding, it is very necessary to identify the hybrid progenies in their early stage and detect their adaptability to temperature. In the study, four hybrids,'Snow Queen'×L. callosum,'Snow Queen'×L. davidii,'Snow Queen'×L. dauricum and'Snow Queen'×L. pumilum, were identified by morphological observation and RAPD(random amplified polymorphic DNA) techniques. Seedlings of four progenies and their parents were treated in chambers with temperatures of 25℃, 28℃, 31℃, 34℃, 37℃and 40℃, the changes of relative conductivity, chlorophyll content, proline content, soluble protein content, SOD(superoxide dismutase) activity, chlorophyll fluorescence parameters and root activity were determined. It was expected to provide references for lily heat-tolerance breeding.The main results were as follows:1. The morphological traits of four progenies were situated between the parents.'Snow Queen'×L. callosum and'Snow Queen'×L. davidii had slender leaves, which was quite similar to their male parents; The leaf shape of'Snow Queen'×L. dauricum and'Snow Queen'×L. pumilum were quite similar to their female parent. The rooting rate and root number of all the hybrid seedlings were higher than those of their parents, showing heterosis and strong vitality.2. Twenty-two random primers with higher polymorphism were used and the results showed that the four progenies were all true hybrids, containning DNA of female and male parents. The percentage of'Snow Queen'×L. callosum bands that come from female parent was 40.38%, from male parent was 44.23%, and new bands absent in the parents were 15.38%. The percentage of'Snow Queen'×L. davidii bands that come from female parent was 33.33%, from male parent was 43.75%, and new bands absent in the parents were 22.92%. The percentage of'Snow Queen'×L. dauricum bands that come from female parent was 48.65%, from male parent was 29.73%, and new bands absent in the parents were 21.62%. The percentage of'Snow Queen'×L. pumilum bands that come from female parent was 65.91%, from male parent was 15.91%, and new bands absent in the parents were 18.18%.3.According to the changes of physiological indexes, all the indexs showed a certain tendency except the maximal PSⅡefficiency Fv/Fm in the leaves with different treatments. Under different temperatures, physiological indexes tendency of parents and progenies were similar. From 28℃, most of the seedlings showed the temperature stress and all the seedlings appeared heat tolerance under 31℃, but were badly hurted under 37℃.4. The heat tolerance of four progenies was better than their female parent, showing heterosis in a certain extent. It was found that there were some differences of heat tolerance among the four progenies. The ranks of heat tolerance of them were'Snow Queen'×L. davidii ,'Snow Queen'×L. dauricum,'Snow Queen'×L. callosum, and'Snow Queen'×L. pumilum.5. Hybrid F1 of'Snow Queen'×L. dauricum flowered and yielded self fertility seeds after one year cultivation. The flower shape, color and bulbs of hybrids were quite similar to their female parent'Snow Queen', but with a self-fertility tendency to their male parents L. dauricum.