Studies On The Main Characteristics And Combining Ability Of 5 Indica Photo-thermo-sensitive Genic Male Sterile Lines

Five new photo- and thermo-sensitive genic male sterile (PTGMS) lines of indicarice, Hua884S, Hua885S, Hua886S, Hua893S, Hua328S, developed newly by HuazhongAgricultural University, and Pei'ai64S (CK) were used in the research. The characteristicsof fertility alteration were investigated through identifying in controlled climatic chamberand continous interval sowing at Wuhan. Meantime, the botanical morphology, floweringhabits and outcrossing characters were systematically studied. In addition, six PTGMSlines were used for female parents, and six new developed restorer lines, Huahui2185,Huahui1035, Hua1108, BR06, Hua190 and Huahui No3 were used for male parents. 36crosses were made by using NCⅡdesign. Grain yield and other nine agronomic traitswere investigated. Analysis on combining ability and heterosis were carried out in 2006 attwo ecological sites, Wuhan and Hainan, respectively, and some superior combinationswere selected. The main results are as follows:1. Stable sterility period of the tested PTGMS lines except Hua885S was longer thancontrol Pei'ai64S and was over 60d at Wuhan in both 2005 and 2006. Hua884S, Hua886S,Hua893S and Hua328S showed thermo- sensitive, while Hua885S showed sensitive tophotoperiod.2. The sensitive stages and critical point of temperatures (CTP) of fertility alteration in sixlines were different. The sensitive stage of Hua884S was from 18d to 9d before heading,the CTP was 24.8℃; the sensitive stage of Hua885S was from 24d to 13d before heading,the CTP was 23.6℃; the sensitive stage of Hua886S Was from 21d to 11d before heading,the CTP was 23.3℃; the sensitive stage of Hua893S were from 20d to 9d before heading,the CTP was 25.0℃; the sensitive stage of Hua328S were from 22d to 5d before heading,the CTP was 23.7℃; the sensitive stage of Pei'ai64S was from 22d to i3d before heading,the CTP was 23.9℃.3. Flowering duration of single plant and single panicle of Hua885S was the shortest, andwas siminal to control Pei'ai64S. Hua893S and Hua328S are comparatively longer.Flowering kinesis each day in a panicle of Hua884S, Hua885S, Hua886S and Hua893Swas better than control Pei'ai64S. The anthesis time of Hua884S, Hua886S, Hua893S andHua328S was more concentrated, while Hua885S and Pei'ai64S's are relatively dispersed.The number of flowering spikelets daily for the tested PTGMS lines except Hua328S wasmore than control Pei'ai64S.4. The distance of opened glume tips and the opening angle of spikelet of Hua893S wasthe largest, 4.91mm and 34.43°, respectively, while Pei'ai64S was the smallest. The orderof spikelets opening time from long to short was Hua886S, Hua893S, Hua885S,Pei'ai64S, Hua884S, Hua328S. As for the stigma exsertion rate, Hua893S was 91.20％,the highest in the studed lines. Hua886S, Hua885S and Pei'ai64S were higher than 83％.The stigma area of Hua893S, Hua886S and Hua884S was larger than 0.90 mm~2, that ofother tested PTGMS lines was smaller than 0.90 mm~2. The lasting time of the stigma vitality of Hua893S was the longest, the stigma vitality of Hua893S, Hua328S andPei'ai64S dropped slowly.5. Both general combining ability (GCA) and specific combining ability (SCA) weresignificant at 5％or 1％levels for main traits. The additive effects were more importantthan non-additive effects except panicles per plant. Effects of the GCA and SCA onvarious characters were not significantly related each other. There were significantdifferences on the GCA and SCA at two ecological sites, Wuhan and Hainan.6. The average competitive heterosis of grain yields was 7.83％at Wuhan and 2.80％atHainan, respectively. The competitive heterosis of seed setting rate was the highest atWuhan, the average value was 9.05％, ranging from -9.61％～33.12％. The competitiveheterosis of panicles per plant had the highest potential at Hainan, the average value was15.65％, ranging from -3.77％～39.62％.7. Hua884S, Hua886S and Hua893S were better among female lines, and Huahui2185,Hua1108 were better among male lines. Hua893S/Huahui2185, Hua884S/Huahui2185,Hua884S/Huahui1035, Hua885S/Huahui2185, Hua328S/Huahui2185 andHua886S/Huahui2185 were superior combinations among hybrids.