Abstract:

The anatomization, effects on agronomic characters, inheritance and gene location of clustered character in different rice resources have been analyzed by some researchers. Z1820, a new spontaneous mutant with clustered spikelets gene (Cl-gene), was founded in breeding materials. Restorers (LH17 and N45) as recurrent female parents and Z1820 as non-recurrent parent, two NILs (Cl-LH17 and Cl-N45) were obtained in the purpose of studying the effects on agronomic characters, gene location of this Cl-gene. The method of morphologic comparability and the technology of SSR marker were introduced into the polymorphism analysis and the near-isogenic level evaluation on those two pairs of Cl-NILs. The main results are as follow: (1) For LH17 and Cl-LH17, there was significant difference in plant height and panicle length but not in effective tillers per plant, spikelets per panicle and percentage of grain setting; for N45 and Cl-N45, there was significant difference only in panicle length (Table 1). (2) Among the detected 120 pairs of SSR primers (10 pairs every chromosome), only RM7434 on chromosome was amplified polymorphic bands between LH17 and Cl-LH17, but there are four primers (RM6297 ,on chromosome; RM587, 7434 ,on chromosome 6; RM3583, chromosome 7) which were produced polymorphic bands in N45 and Cl-N45; Another four SSR primers near RM7434 were produced polymorphic bands in NILs and their recurrent parents, and RM5957 was a polymorphic primer to LH17 and Cl-LH17 but not to N45 and Cl-N45. (3) The numbers of double, three and four-clustered spikelets in Cl-N45 were all bigger than those in Cl-LH17 and the clustering level (based on clustered rate) of Cl-N45 was also bigger than that of Cl-LH17. Those results indicated that the plant height and panicle length were decreased by Cl-gene from Z1820 but effective tillers per plant, spikelets per panicle, and percentage of grain setting were not changed; LH17 and Cl-LH17 are one pair of ideal Cl-NILs and they can be propitious to be used in the lucubration of the Cl-gene; the spikelets-clustered phenotype was different in different genetic background. The high quality NILs can be easily developed and the near-isogenic level can be objectively evaluated by the combining utilization of classical methods and modern molecular marker technologies.

Key words: Clustered spikelets, Near-isogenic lines, Evaluation, Rice