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Diallel Analysis of Wheat streak mosaic virus Resistance in Winter Wheat


This article in CS

  1. Vol. 44 No. 1, p. 89-92
    Received: Aug 7, 2002

    * Corresponding author(s): amir_ibrahim@sdstate.edu
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  1. Frederic Hakizimanaa,
  2. Amir M. H. Ibrahim *a,
  3. Marie A. C. Langhama,
  4. Scott D. Haleyb and
  5. Jackie C. Ruddc
  1. a Plant Science Dep., South Dakota State Univ., Brookings, SD 57007
    b Soil and Crop Sciences Dep., Colorado State Univ., Fort Collins, CO 80523
    c Texas Agric. Exp. Stn., 6500 Amarillo Blvd. W., Amarillo, TX 79106


Wheat streak mosaic virus (WSMV) (Family: Potyviridae; Genus: Tritimovirus), disseminated naturally by the wheat curl mite (Aceria tosichella Keifer), is an important disease of wheat (Triticum aestivum L. em Thell.) worldwide. Breeding for resistant cultivars remains the best strategy to control the disease. Nine winter wheat genotypes with differential reaction to WSMV were crossed in a complete diallel mating design to determine the combining ability of WSMV resistance. Parents, F1, and reciprocal crosses were inoculated at the seedling (2–3 leaves) stage with a WSMV-SD isolate and evaluated for reaction under greenhouse conditions. Disease reaction was assessed twice (at 1-wk intervals) by a 1-to-5 scale (1 = no visible symptoms to light green streaks, 5 = severe yellow streaks and necrosis). Data were analyzed according to Griffing's Method 3 and Model 1, where one set of F1 and reciprocal F1 are included. Highly significant genotype effects (P < 0.01) were observed for WSMV resistance. General combining ability (GCA) and specific combining ability (SCA) effects for WSMV resistance were highly significant (P < 0.01), indicating that both additive and nonadditive genetic effects are involved in the inheritance of WSMV resistance. The reciprocal effects were not significant (P > 0.05). The ratio of combining ability variance components [(2σ2 GCA)/(2σ2 GCA + σ2 SCA)] was small (0.1), indicating that nonadditive (i.e., dominance and epistasis) gene effects were more important than additive gene effects in controlling WSMV resistance in these crosses; therefore, progeny performance cannot be adequately predicted from GCA effects alone.

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