[Objective]Rice tiller angle is an important plant-type trait. The appropriate tiller angle is generally a critical factor in developing ideal-type high-yielding rice variety. [Methods]Effects of tiller angle controlling gene TAC1 on agronomic traits, sheath blight resistance, grain yield and quality were investigated under conditions of one-plant one-point and multi-plants one-point transplantation by using four pairs of near isogenic lines(NILs) at TAC1 gene.[Results]TAC1 increased rice tiller angle in all the genetic backgrounds tested, which is beneficial for reducing adverse impacts of sheath blight, without affecting other agronomical traits. Under high-yielding cultivation condition of multi-plant one-point transplantation, numbers of effective panicles in all the NILs with TAC1 were apparently higher than those of corresponding NILs with tac1. In the background of indica rice Teqing, the seed-setting rate, 1000-grain weight and plant yield of Teqing-TAC1 line were all higher than those of Teqing-tac1 line; however, the reverse results were obtained in the background of Lemont. In backgrounds of Wulingjing 1 and Zhendao 88, NILs with TAC1 gene displayed slightly grain yield than those with tac1 gene. The grain processing and appearance qualities of Teqing-TAC1 line were slightly improved compared to the corresponding control, while other TAC1-harboring NILs showed just the reverse with statistically insignificant difference. [Conclusions]The indica rice with long leaf has a narrow range of appropriate tiller angles but for japonica rice with short leaf, the range is wider. Increasing rice tiller angle to an extent is beneficial for reducing sheath blight influence. TAC1 improves the plant type of japonica rice as well as the compact type indica rice.

Appropriate leaf rolling index is one of the important morphological traits in rice breeding for ideal plant type. According to the NCⅡheredity mating design, we used five near?isogenic lines ( NILs) showing various leaf rolling index respective to cross with five restorer lines to obtain 25 hy?brid rice lines. By investigating 10 important agronomic traits on these hybrid rice lines, combining abilities of the five NILs were evaluated as well as the heritability of each trait. Results showed that:the three traits of spikelet number per plant, seed setting ration and heading date were mainly genet?ically controlled by gene additive effects, showing the highest heritability. In total, the remaining six traits were genetically controlled by both gene additive and non?additive effects, and among them flag leaf width was mostly affected by non?additive effect. Leaf rolling indexes of the hybrid rice lines were mainly affected by parents of NILs. The QMX( YSBR1) NIL had high general combining ability ( GCA) effect, revealed by the higher plant yield of hybrid rice lines developed by this NIL, demon?strating QMX(YSBR1) was the best hybrid rice breeding parent, followed by QMX(5408)and QMX ( PS) NILs. These results will offer valuable references for further developing high?yield hybrid rice with rolled leaf as well as for identifying leaf rolling genes with high breeding potential.

Indica rice cultivar Teqing and japonica rice cultivar Zhendao 88 were used as the donor parents with the sheath blight (SB) resistance QTL qSB-9 TQ and the resistance gene Stv-b i , respectively.Commercial rice japonica cultivars, Wuyujing 3 and Wujing 15, were used as the receipt parents to cross and backcross with the donor parents, respectively.Flanked polymorphic markers to the two loci were developed and employed to select the target loci via marker assisted selection (MAS) in each backcross and self-cross progeny.Till backcross generation BC 4 F 1 , pyramiding was performed by crossing the selected individuals with different integression genes.At F 3 generation, the pyramiding lines with homozygosity at both gene loci were obtained.Results of disease resistance evaluation indicated that both pyramiding lines were resistant to stripe disease, and increased resistance to SB with a reducing SB sating of 1.1-1.6 in Wuyujing 3 background and 0.8-1.4 in Wujing 15 background based on a "0-9" SB rating scale.Combining the results of resistance phenotype at the low backcrossing generation, we thought the markers developed in this study were efficient in selecting the two genes by MAS.Some questions associated with SB resistance breeding and pyramiding breeding via MAS were discussed.

By using Qimiaoxiang as recurrent parent and four leaf rolling materials(5408,JuanzhenB,YSBR1 and Peiai64S) as non-recurrent parent,a set of near isogenic lines(NILs) on leaf rolling in BC_7F_3 generation were obtained to study the effects of different leaf rolling gene.The main results were as follow: there was very significant difference in leaf rolling index of flag leaf(LRI) among four NILs,and there was significant difference in cardinal angle of flag leaf,primary branch number per panicle and 1000-grain weight between partial NILs and Qimiaoxiang,and there was no significant difference in other characters between four NILs and Qimiaoxiang F_1 generations from cross between 4 NILs and Qimiaoxiang had significant difference in LRI of flag leaf,and their LRIs were less than mean value of parents,therefore,it was speculated that character of rolling leaf was controlled by recessive gene.Further study on character and gene of rolling leaf using NILs was discussed.