麦秸还田和结实期灌溉方式对超级稻籽粒结实和米质的影响

以大穗型超级杂交粳稻‘甬优8号’为材料,设置麦秸还田(麦秸全量还田与麦秸不还田)和结实期灌溉方式(浅水层灌溉、轻干湿交替灌溉和重干湿交替灌溉)两因素试验,研究其对大穗型超级稻籽粒结实和主要米质性状的影响。结果表明:结实期灌溉方式对籽粒结实性状有显著影响。在麦秸还田与麦秸不还田下,与浅水层灌溉相比,轻干湿交替灌溉显著提高了‘甬优8号’的千粒重、结实率、充实度,而重干湿交替灌溉则相反;麦秸还田处理下籽粒结实性状均优于秸秆不还田处理,麦秸还田与结实期轻干湿交替灌溉互作可以改善超级稻‘甬优8号’的结实性状;与麦秸不还田相比,麦秸还田提高了籽粒的整精米率、粗蛋白含量和消减值,降低了垩白率、垩白度、直链淀粉含量、胶稠度和崩解值;与浅水层灌溉相比,轻干湿交替灌溉降低了直链淀粉含量、粗蛋白含量和消减值,提高了整精米率、垩白率、垩白度、胶稠度和崩解值,但重干湿交替灌溉则使米质明显变差;两处理对弱势粒的主要稻米品质的调控作用大于强势粒。在麦秸还田下,结实期轻干湿交替灌溉可以较好地协调‘甬优8号’结实性状和稻米品质间的关系。

Effects of returning wheat straw to farmland and irrigation pattern on grain setting traits and quality of super rice

Environmental conditions during grain filling stages can affect grain setting traits and quality of rice. To have high yield and quality of super rice, the effects of returning wheat straw to farmland and irrigation patterns on yield characteristics and qualities of superior and inferior grains of the super rice cultivar 'Yongyou 8' were investigated. Returning wheat straw to farmland included two treatments all wheat straw return (T1) and no wheat straw return (T0)] while the irrigation patterns included three treatments alternate wetting and moderate soil drying (W1), in which soil was re-watered when 15?20 cm soil water potential reached ?20 kPa; alternate wetting and severe soil drying (W2), in which soil was re-watered when 15?20 cm soil water potential reached ?40 kPa; and water-saving irrigation (W0)]. The results showed that irrigation patterns significantly influenced grain setting traits during rice grain filling stage. Compared with the W0, W1 significantly enhanced 1000-grain weight, grain setting rate and grain plumpness index, while W2 showed the contrary effects. The grain setting traits of T1 treatment were better than those of T0. The interactions of T1 and W1 improved the grain setting traits of 'Yongyou 8'. Compared with T0, T1 increased head milled rice rate (HMRR), crude protein content (CPC) and setback viscosity (SBV), but decreased percentage of chalky kernel (PCK), chalkiness degree (CD), amylase content (AC), gel consistency (GC) and breakdown viscosity (BDV). Compared with W0, W1 increased HMRR, PCK, CD, GC, BDV while it decreased AC, CPC and SBV. However, rice grain quality was bad under W2 treatment. The regulatory roles of different treatments in inferior grains were significantly greater than those in superior grains on the grain quality. In the case of T1, W1 coordinated the relationship between the grain setting traits and rice grain quality of 'Yongyou 8'.