广西普通野生稻渗入系耐低氮和氮素利用率的鉴定评价

以广西普通野生稻Y11为供体,籼型恢复系GH998为受体构建的166份野生稻渗入系BC₃F₅为研究对象,设置不施氮（LN）和正常施氮（NN）2种处理,调查株高、有效穗和穗长等12个表型性状,结合耐低氮（NDT）性状、氮素利用率（NUE）性状进行综合评价,以筛选出可利用的氮高效利用育种材料。结果表明：渗入系所有表型均值NN处理均高于LN处理,受施氮影响较大的性状为茎叶含氮量和谷物含氮量,增幅分别为56.89%和37.89%;影响较小的性状为穗长和千粒重,增幅分别为0.50%和2.76%;除穗长外,11个性状在2个施氮处理间呈极显著差异,而且穗总粒数、穗实粒数呈正态分布。渗入系NDT性状的相对生物产量（RBY）与相对生物含氮量（RBN）均值居于双亲之间,且RBN为正态分布;相对谷物产量（GRY）和相对谷物含氮量（RGN）均值高于双亲且趋近GH998,均为正态分布;说明渗入系的耐低氮能力与野生稻的高生物产量和高谷物含氮量特性相关。NUE性状均值处于双亲之间且趋近于GH998,说明氮素高效利用能力主要来源于栽培稻;NDT和NUE性状之间呈显著负相关,因此提高水稻耐低氮能力会降低氮高效利用率。NDT性状的主要影响因子是谷物含氮量和茎叶干重;NUE性状主要影响因子是有效穗、单株产量和谷物产量等。因此,依据研究结果对渗入系进行综合评价筛选,获得3个耐低氮、12个高氮素利用率和3个氮高效且耐低氮的株系,为水稻氮高效育种提供理论依据和育种材料。

Identification and Evaluation of Nitrogen-deficiency Tolerance and Nitrogen-use Efficiency for Introgression Lines of Wild Rice (Oryza rufipogon Griff.) in Guangxi

In order to utilize the elite genes of wild rice, 166 BC₃F₅ introgression lines constructed from Guangxi wild rice Y11 as the donor and Indica restorer line GH998 as the recipient were used as the identification materials. Twelve phenotypic traits were studied under low nitrogen (LN) and normal nitrogen (NN) treatments. Combined with nitrogen-deficiency tolerance (NDT) and nitrogen-use efficiency (NUE) traits, a comprehensive evaluation was conducted in order to select available nitrogen-efficient breeding materials. The results showed that the mean value of 12 phenotypes in NN were higher than that of LN. The nitrogen content of stem-leaf and grains were strongly affected by nitrogen fertilizer, improved by 56.89% and 37.89%, respectively. The panicle length and 1000-grain weight were less affected, improved by 0.50% and 2.76%, respectively. Except for spike length, 11 traits showed extremely significant differences between LN and NN. Total grains per panicle and filled grains per panicle were normal distributed. The mean value of relative biomass yield (RBY) and relative grain yield (RBN) of NDT traits in the introgression lines were located between the parents, and RBN was normal distribution. The mean value of relative grain yield (RGY) and relative grain nitrogen (RGN) were higher than those of the two parents and close to GH998. All NDT traits were normal distribution. It indicated that NDT of introgression lines was correlated with high biomass yield and grain nitrogen content of wild rice. The mean value of NUE traits were located between the two parents and close to GH998, which indicating that the high NUE mainly was affected by cultivated rice. Moreover, NDT was significantly negatively correlated with NUE. So, improving NDT level would reduce the level of NUE. The grain nitrogen content, dry weight of stems and leaves were key impact factors of NDT. The panicle number, yield per plant and grain yield were key impact factors of NUE. Finally, based on these studies, 3 lines with high NDT, 12 lines with high NUE and 3 lines as both traits were comprehensively evaluated, which would provide theoretical basis and special germplasm for rice breeding in nitrogen efficient.