水旱生态型冬小麦品种杂种优势分析

为了了解冬小麦水旱生态型杂种优势表现,在雨养条件下,选用水旱两种生态型的小麦品种各4个,组成4×4不完全双列杂交,分析了F_1代株高(X_1)、穗下茎长(X_2)、单株穗数(X_3)、穗粒数(X_4)、千粒重(X_5)、单株生物产量(X_6)、单穗重(X_7)、单株粒重(Y)等8个主要农艺性状的杂种优势及各性状优势间的相关性,并进行了通径分析。结果表明,F_1杂种优势普遍存在。单株粒重的平均优势最高,其次是单株生物产量。产量三要素平均优势以千粒重优势最高,单株穗数次之,穗粒数优势最低。各性状不同组合的杂种优势间存在较大变异。各个性状优势对产量优势的贡献排序为X_3>X_4>X_5>X_6>X_7>X_2>X_1。其中,单株穗数对产量优势的直接效应最高,穗下茎长和单株生物产量对籽粒产量主要起间接作用,与单株粒重优势相关达显著和极显著水平。试验表明,旱地小麦高产育种应注意选育分蘖力强,成穗率高,穗下颈较长,具有一定株高和生物产量的品种,在保持一定穗数的基础上,协调好千粒重与穗粒数及其它农艺性状的关系。

Heterosis of Winter Wheat Crossed between Irrigated-Field Varieties and Dry-field Varieties

In order to study the heterosis of winter wheat crossed between irrigated-field varieties and dry-field varieties, the 4@4 incomplete dialed cross was exploited between 4 irrigated-field and 4 dry-field winter wheat varieties in rain-fed condition. The heterosis of major agronomic characters and their relationships were analysed. 8 agronomic characters i.e. plant height(X1), internode length below spike (X2), spikes per plant (X3), grains per spike (X4), 1000-kernel weight (X5), biomass per plant (X6), grain weight per spike (X7) and grain yield per plant (Y) were studied through path analysis. The results showed that the heterosis of F1 were exited widely. The heterosis of grain yield per plant was the highest, the heterosis of biomass per plant was the second. Among the three main yield components, the heterosis of 1000-kernel weight was the highest, the heterosis of spikes per plant was the second, the heterosis of grains per spike was the lowest. The heterosis of all characters had a large range of variation. The order of heterosis contributed by the seven characters to grain yield per plant was X3>X4>X5>X6>X7>X2>X1. Among the direct effects contributed by the seven characters to grain yield per plant, the heterosis of spikes per plant was the highest. Through indirect effects, the correlation between grain yield per plant and the characters for internode length below spike, biomass per plant were siginificant or highly siginificant. The results indicated that dry-field winter wheat breeding should follow the way of stronger tillering ability, higher rate of spike-bearing, longer internode below spike, suitable plant height and biomass per plant, coordinating well the relationship of the 1000-kernel weight and grains per spike as well as other agronomic characters.