不同生育期分时段弱光胁迫对水稻产量、干物质积累与稻米品质的影响OA

To clarify the effects of different weak light durations at key growth stages and different periods of weak light stress at the same growth stage on rice yield and quality,conventional japonica rice Nanjing 9108 and indi-ca-japonica hybrid rice Yongyou 2640 were used as test materials in this study.Weak light treatments with three durations(7 d,14 d,21 d)and three periods of 7 d at the same growth stage were set at tillering stage,jointing stage and filling stage of rice,and natural light was used as control(CK)to analyze the effects of different weak light treatments on rice yield,dry matter accumulation and rice quality.The results showed that weak light treatments for 14 d and 21 d at three growth stages led to yield reductions in Nanjing 9108 and Yongyou 2640.The greatest yield reduction occurred under the weak light treatment for 21 d at jointing stage,and the yield of Nanjing 9108 and Yongyou 2640 decreased by 16.79%and 23.04%,respectively,compared with CK.With the prolongation of weak light duration,the yield reduction became greater.The main reasons for yield reduction at tillering stage,jointing stage and filling stage were the decrease of effective panicle number,grain number per panicle,seed setting rate and 1 000-grain weight,respectively.There was no significant difference in dry matter accumulation at ma-turity stage of Nanjing 9108 under low light treatment for 7 d at early and middle tillering stages compared with CK.Howev-er,for all other weak light treatments,the dry matter accumulation of the two varieties was significantly lower than that of CK.Among them,the dry matter accumulations of Nanjing 9108 and Yongyou 2640 treated with low light for 21 d at joint-ing stage were 18.20%and 23.10%lower than those of CK,respectively,and the decreases were the largest.The low light treatment at tillering stage and jointing stage generally had little effect on the rice quality of the two varieties,while the milled rice rate of Nanjing 9108 treated with low light for 14 d and 21 d at filling stage was 7.37%and 26.49%lower than that of CK,and the milled rice rate of Yongyou 2640 was 7.95%and 13.34%lower than that of CK.The chalky grain rate and chalkiness degree of Nanjing 9108 were significantly decreased under the low light treatment for 21 d at grain filling stage,while the chalky grain rate and chalkiness degree of Yongyou 2640 were significantly increased.Compared with CK,low light treatments for 14 d and 21 d at grain filling stage could significantly increase the protein content of Nanjing 9108 and Yongyou 2640,reduce the amylose content,and reduce the viscosity,balance and taste value of rice.