不同施氮量下籼/粳杂交稻甬优2640产量和氮素吸收利用的特点

旨在探明在不同施氮量下籼/粳杂交稻产量、氮素吸收利用及损失的特点。2018—2019年籼/粳杂交稻品种甬优2640和常规粳稻品种连粳7号(对照品种1)和常规籼稻品种扬稻6号(对照品种2)种植于大田,设置6种施氮量(0、100、200、300、400和500 kg hm^(-2))处理和^(15)N示踪微区试验。3个供试品种的产量均随施氮量的增加呈现先增加后降低的趋势,甬优2640在施氮量为400 kg hm^(-2)时产量最高,连粳7号和扬稻6号均在施氮量为300 kg hm^(-2)时产量最高。在相同施氮量下,甬优2640的产量高于对照品种。^(15)N示踪试验表明,适量增加施氮量(甬优2640≤400 kg hm^(-2)、连粳7号和扬稻6号≤300 kg hm^(-2)),可以增加成熟期植株和穗中肥料氮积累量、土壤中的残留量、肥料氮对植株地上部氮积累量的贡献率、肥料氮的损失量和损失率,降低土壤氮对植株地上部氮积累量的贡献率、肥料氮的植株吸收利用率和在土壤的残留率。在相同施氮量下,甬优2640的肥料氮吸收量、在穗中的积累量、对植株地上部氮积累量的贡献率均高于对照品种,肥料氮的损失量、损失率、在土壤的残留率均低于对照品种。肥料氮的21.0%~35.7%、6.7%~23.7%和42.3%~72.6%分别被植株吸收、残留在土壤中以及流失到了生态系统中。在相同施氮量条件下,与常规高产品种相比,籼/粳杂交稻甬优2640的产量和氮吸收利用率均较高,氮损失率较低。在本试验条件下,甬优2640产量和氮肥利用效率协同提高的施氮量为300 kg hm^(-2),产量可达13.0 t hm^(-2)。

Breeding of New Japonica-indica Hybrid Rice Combination——Chunyou 618

[Objective] The aim was to select and breed Chunyou 618 which is a novel combination among japonica-indica hybrid rice subspecies. [Method] Chunyou 618 is a japonica-indica hybrid rice combination developed from Chunjiang 16A, a late japonica CMS line with dwarfness and early anthesis time, and C18, an indicaclinous wide compatibility restorer line. In addition, the concerning characters were researched. [Result] Chunyou 618, which is japonica inclining, proved high in pro- duction and in resistance to lodging with Cheng＇s index at 15. It is of moderate re- sistance against Xanthomonas oryzae and stripe virus disease, of moderate susceptibility on rice blast, and of susceptibility on Nilaparvata lugens. The indices of rice quality achieved departmental standard 4 and grade 4 of Cooking Rice Variety Quality, respectively. [Conclusion] Chunyou 618 enjoys strong heterosis, strong stem, good lodging resistance, large panicles, good cold tolerance, high yield and wide adaptability, which is suitable to be grown in Zhejiang Province as single cropping late rice.

Genetic Effects and Heterosis in Plant Height and Internode Traits of Japonica-Indica Hybrid Rice

[Objective] This study aimed to investigate the genetic effects and heterosis of plant height and internode traits of japonica-indica hybrid rice. [Methed] Incomplete diallel crosses were made between six japonica CMS lines and nine indica widecompatibility restorer lines; the genetic effects of plant height and internode traits of japonica-indica hybrid rice were analyzed using the additive-dominance genetic model. [Result] The ple, nt height, panicle length and the length of internode 1 of japonica-in- dica hybrid rice were mainly controlled by the additive effects; but the length of in- ternode 3, internode 4 and internode 5 were mainly controlled by dominance effects. Both the narrow sense heritability and broad sense heritability of plant height, panicle length, number of elongated internodes and length of most internodes reached signifi- cance level. The positive phenotypic correlation, genetic correlation, additive correla- tion and dominance correlation between plant height and panicle length, number of e- longated internodes and internode length were significant; and most of the other paired traits were significantly positively correlated. Heterosis analysis showed that the positive heterosis value over mid-parent and positive heterosis value over better- parent of the length of internode 3, internode 4, internode 5 and internode 6 reached significant level, and the heterosis value over mid-parent of plant height reached extreme significance level. [Conclusion] This study will provide reliable theoretical basis for the genetic improvement and heterosis utilization of plant height and internode traits in japonica-indica hybrid rice.