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Crop Science Abstract -

Breeding Methodology in Wheat. I. Determination of Characters Measured on F2 Spaced Plants for Yield Selection in Spring Wheat1


This article in CS

  1. Vol. 20 No. 5, p. 583-586
    Received: Oct 9, 1979

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  1. P. B. E. McVetty and
  2. L. E. Evans2



Three crosses of spring wheat (Triticum aestivum L.) involving the cultivar ‘Glenlea’ as a common female parent were used to evaluate the use of physiological and/or morphological parameters alone or in combination on F2 plants as selection criteria to identify high-yielding F4 bulks. The F2 generation was grown as spaced plants in the field under two types of environmental regimes: (1) a regime and (2) a normal regime. Stress-free plants were given regular irrigation, optimum fertilization and complete weed control to minimize stress while the normal-regime plants were given no special treatment. Two hundred plants of each cross were measured for physiological, morphological, yield-component, and phenological traits. A random sample of 50 seeds from each of these plants was used to generate F4 bulks. For each cross, groups of 45 F4 bulks derived from stress-free F2's and 75 F4 bulks derived from normal F2's were tested for yield in the F4 in a six-replicate, partially balanced lattice design.

The results indicated that single F2 parameters which described source capacity, sink capacity or plant morphology all identified high-yield potential in the F2; however, at 15% selection intensity only 17 out of 53 high-yielding F4 bulks were retained. A multiple regression analysis was found to be better than a single parameter approach, retaining nearly half (24 out of 53) of the high-yielding lines. A combined-cross analysis indicated that yield, productivity, kernel number, peduncle length, and productivity per tiller were all significantly correlated with F4 bulk yields. A multiple regression analysis of the combined crosses indicated that productivity and peduncle length were the only significant common parameters

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