小麦苗期耐低氮基因型的筛选与评价

氮是作物吸收的第一大必需营养元素, 对作物生长发育具有不可替代的作用。大量研究表明, 不同基因型小麦对氮的吸收利用能力不同, 培育氮高效小麦品种是提高氮利用效率的根本途径, 而发掘耐低氮小麦种质资源是小麦氮高效育种的基础。为此, 本研究以30 个小麦-冰草远缘杂交的高代品系, 1 个小麦-黑麦远缘杂交的T1BL·1RS 易位系, 2 个"小偃54"×"京411"重组自交系群体中的品系, 以及13 个生产上的主栽品种为试验材料, 通过低氮胁迫和正常供氮2 个处理的苗期水培试验, 进行了耐低氮基因型的筛选与评价。方差分析显示, 13 个氮效率相关性状在2 种氮水平之间及各小麦基因型之间的差异均达到显著或极显著水平。主成分分析显示, 前3 个主成分累积贡献率达到81.2%, 已包含了大部分信息, 能够基本反映整体状况。其中, 相对茎叶吸氮量、相对植株吸氮量、相对根冠比、相对茎叶干重、相对植株干重、相对茎叶氮利用效率、相对根含氮量在3 个主成分中占较大的比重。综合评价结果显示, 在33 个小麦远缘杂交品系中08B41 得分最高, 为1.60,为最耐低氮的品系; 13 个主栽品中"科农9204"得分最高, 为2.10, 为耐低氮的品种。聚类分析显示, 46 份基因型小麦可划分为3 大类: 耐低氮型(15 份)、中间型(22 份)和低氮敏感型(9 份)。筛选出08B41、XJ19-1、08B8、08B10、08B13、08B25、WR9603、08B2、08B5 共9 份耐低氮远缘杂交高代品系, 及"科农9204"、"邯7086"、"河农827"、"石麦18"、"石4185"、"石新733"共6 份耐低氮主栽品种。这些耐低氮的基因型可作为小麦营养高效育种的种质资源, 本文并对小麦近缘种属在小麦营养高效遗传改良中的作用进行了讨论。

Screening and evaluating low nitrogen tolerant wheat genotype at seedling stage

Nitrogen tops the list of crop macro elements essential for plant growth and development. Several studies have shown that under low nitrogen conditions, crop species/genotypes vary widely in nitrogen uptake ability and utilization efficiency. Planting wheat cultivars with high nitrogen efficiency is the fundamental way to raise nitrogen utilization efficiency; and exploiting nitrogen tolerant wheat germplasm resources is the basic of breeding wheat varieties with high nitrogen efficiency. To this end, 30 advanced distant hybridization lines of wheat and wheatgrass, one T1BL·1RS translocation line of distant hybridization of "Xiaoyan 6" and "Germany white" (rye), two recombinant inbred lines of "Xiaoyan54 × Jing411" and 13 commercial wheat varieties, were screened and evaluated for low nitrogen tolerant genotypes in hydroponic culture at seedling stage. Analysis of variance showed significant to very significant differences in 13 nitrogen efficiency related traits between two nitrogen treatments and among genotypes. Principal component analysis showed that the first three principal components had an accumulative contribution rate of at least 81.2%, implying that they contained most of the information to reflect the overall trait resources. The proportions of relative shoot/plant nitrogen uptake, root/shoot ratio, shoot dry weight, plant dry weight, shoot nitrogen utilization efficiency and root nitrogen content of the three principal components were significantly high. A comprehensive evaluation suggested that 08B41 had the highest score (1.60) for the best nitrogen tolerant wheat line in the 32 distant wheat hybridization lines. Then "Kn9204" had the highest score (2.10) for the best nitrogen tolerant wheat variety in the 13 commercial wheat varieties. Clustering analysis showed that the 46 wheat genotypes were broadly categorized into 3 groups (low nitrogen tolerant type, medium nitrogen tolerant type and low nitrogen sensitive type with 15, 22 and 9 genotypes, respectively). 9 advanced distant hybridization lines (08B41, XJ19-1, 08B8, 08B10, 08B13, 08B25, WR9603, 08B2, 08B5) and 6 commercial wheat varieties ("Kn9204", "Han7086", "Henong827", "Shimai18", "Shi4185", "Shixin733") were noted to have low nitrogen tolerance. These low nitrogen tolerant genotypes were utilizable in breeding N-efficient wheat varieties. The study also discussed the roles of wheat related species in improving the genetic makeup of N-efficient wheat varieties.