Studies On The Outcrossing Habits Of CMS Lines And Genetic Diversity Of CMS Lines

These researching objects are 24 Cytoplasmic Male Sterile (CMS) lines of hybrid rice that were widely popularized in Sichuan Province and other province. We have done Correlation Analysis and Path Analysis between seven agronomy traits of these CMS lines and Outcrossing Rate in Hybrid Rice Seed Production. We also observed the time and characteristics of abortion in five different typical CMS lines from cell morphology perspective. Meanwhile, we had carried on cluster analysis to these 24 parts CMS lines. The main results are:1. In seven traits, only spikelet opening time and flowering-time have a negative correlation with outcrossing seed-setting rate, and other five traits have a positive correlation with outcrossing seed-setting rate. Through doing Path Analysis, the directly path coefficient between any trait of seven and outcrossing seed-setting rate in Hybrid Rice Seed Production arrange from high to low is: rate of grain in neck, single stigma exsertion, opening angle of spikelet, dual stigma exsertion, flowering duration, flowering-time, spikelet opening time. The direct function of the rate of grain in neck, single stigma exsertion, opening angle of spikelet, dual stigma exsertion, is bigger than their indirect function, it shows these four traits have a close correlation with Outcrossing seed-setting Rate in Hybrid Rice Seed Production. However, the directly path coefficients of spikelet opening time is minus.2. The test by observing 5 different type of CMS lines (D, K, Gang, WA, IN), and finding that the abortion process of these five CMS lines is same. Only in some certain time, they have a little difference. It also has a same abortion process between the type of WA and D, the time of abortion most happened at the stage from monocaryon to dikaryon. However, the Gang, K, IN, these 3 kinds of CMS lines have a familiar abortion process, the time of these 3 kinds is earlier than WA and D types. Generally, they will all abort in monocaryon late phase.3. By using of the SSR marking technique, Out of 34 random primers displayed well in polymorphisms. On the 34 SSR loci, a total of 77 allelic loci were detected. Every primer pairs offered 2.27 allelic loci on average. The value of allelic polymorphism information content (PIC) ranged form 0.08 to 0.559, on an average 0.254 per primer. Cluster analysis was based on the genetic similarity coefficients. The molecular phylogenetic trees constructed by UPMGA showed the genetic relationship among 24 cytoplasmic male sterile (CMS) lines. The results indicated that genetic background was vulnerable among rice male sterile lines in large scale. It suggested that the heterosis were limited for these CMSs in hybrid breeding.