适宜重庆地区直播中稻蓄留再生稻品种筛选及其丰产性分析

【目的】筛选出适宜重庆地区直播中稻蓄留再生稻的优质杂交水稻品种，并探索其产量形成特征，为重庆地区直播中稻蓄留再生稻生产技术的推广提供理论依据。【方法】以15个适宜长江上游地区的中熟和中迟熟优质水稻品种为试验材料，中稻机械化湿润直播蓄留再生稻，通过生育期、再生力、抗折力和产量及其构成因素等指标对参试水稻品种进行综合评价。【结果】参试水稻品种间的生育期、再生力、抗折力和产量及其构成因素差异显著（P< 0.05，下同），在直播中稻蓄留再生稻条件下，全生育期为201～217 d，再生力为0.75～1.36，抗折力为0.89～1.57 kg，中稻产量为6.29～9.90 t/ha，再生稻产量为2.84～4.71 t/ha，两季产量为9.81～12.80 t/ha。以产量为分类变量进行聚类分析，可将参试的15个水稻品种分为中稻高产再生稻高产、中稻高产再生稻中产、中稻中产再生稻中产、中稻低产再生稻高产和中稻低产再生稻中产等5个类型。筛选出中稻高产再生稻高产和中稻高产再生稻中产水稻品种川优5213、川优8213、西优32、川康优637、旌22优占、B优2928和川绿优青粘等7个适宜直播中稻蓄留再生稻水稻品种。不同类型水稻品种产量与各指标的相关分析结果表明，中稻产量与全生育期呈显著正相关，与再生稻生育期呈极显著正相关（P< 0.01，下同），与中稻结实率呈极显著正相关，与中稻千粒重呈显著正相关；再生稻产量与再生稻每穗粒数和再生稻有效穗数呈显著正相关，与再生力呈极显著正相关；两季产量与中稻产量和中稻结实率呈极显著正相关。【结论】川优5213等7个水稻品种适宜直播中稻蓄留再生稻，可作为适宜重庆地区直播中稻蓄留再生稻品种及在种质资源改良中加以利用。

Screening for ratooning rice of direct seeding medium rice varieties suitable in Chongqing area and their high-yield abilities

【Objective】The objective of this study was to screen suitable rice varieties for ratooning rice of direct seeding medium rice in Chongqing and explore the characteristics of yield formation.The results could provide theoretical basis for ratooning rice of direct seeding production technology in Chongqing area.【Method】Fifteen good quality rice varieties of medium maturity and medium-late maturity, suitable for the upper reaches of Yangtze river were used as materials, ratooning rice was maintained from medium rice with mechanized wet seeding.Tested rice varieties were evaluated by using growth period, ratooning ability, break force, yield and yield components and other indicators.【Result】Results indicated that variety had significant difference on growth period, ratooning ability, break force, yield and yield components of medium rice and ratoon rice(P< 0.05, the same below).Under direct seeding condition, the whole growth periods were from 201 to 217 d, and the ratooning abilities were from 0.75 to 1.36, and the break forces were from 0.89 to 1.57 kg, and the medium rice yields were from 6.29 to 9.90 t/ha, and the ratooning rice yields were from 2.84 to 4.71 t/ha, and the total yield of two seasons were from 9.81 to 12.80 t/ha.According to the cluster analysis based on grain yield, there were five rice types among the 15 tested varieties, including HMHR(high-yield medium rice and high-yield ratooning rice), HMMR(high-yield medium rice and middle-yield ratooning rice), MMMR(middle-yield medium rice and middle-yield ratooning rice), LMHR(low-yield medium rice and high-yield ratooning rice) and LMMR(low-yield medium rice and high-yield ratooning rice).The selected HMHR type and HMMR type, including Chuanyou 5213, Chuanyou 8213, Xiyou 32, Chuankangyou 637, Jing 22 youzhan, B you 2928 and Chuanlüyouqingzhan were suitable for ratooning rice of direct seeding medium rice.The correlation analysis showed that the yield of medium rice had significant positive correlation with the whole growth period, extremely significant positive correlation with the growth period of ratooning rice(P< 0.01, the same below), extremely significant positive correlation with the seed-setting rate of medium rice, significant positive correlation with 1000-grain weight of medium rice.The yield of ratooning rice had significant positive correlation with grains per panicle and effective panicles, extremely significant positive correlation with the ratooning ability.The total yield of two seasons had extremely significant positive correlation with the yield of medium rice and the seed-setting rate.【Conclusion】Seven rice varieties such as Chuanyou 5213 are suitable for ratooning rice of direct seeding medium rice.These can be applied in breeding of the suitable rice varieties for ratooning rice of direct seeding medium rice and improvement of rice landraces in Chongqing area.