Diallel Analysis of Gene Effects Conditioning Resistance to Stagonospora nodorum (Berk.) in Wheat

Abstract

Stagonospora nodorum (Berk.) blotch (SNB) is a fungal disease that affects all aboveground parts of wheat (Triticum aestivum L.) plants. Stagonospora nodorum blotch causes serious losses in grain yield and seed quality of wheat grown in the southeastern USA. The objective of this study was to conduct a genetic analysis of components of partial resistance to SNB in wheat. Ten lines of soft and hard winter wheats that varied in resistance to SNB were used in two sets of intrawheat‐class half‐diallel matings. Seedling plants of parents, F1 crosses, and F2 populations were inoculated at the two‐leaf stage with spores of SNB in a humidity chamber to determine incubation period (IP), latent period (LP), and necrosis percentage (NP). The analysis of variance (ANOVA) showed highly significant differences for IP and NP among hard wheat crosses in both Fl and F2 generations. Highly significant differences for IP were noted among soft wheat Fl crosses. Significant differences for NP were observed among soft wheat F1 and F2 crosses. General Combining ability (GCA) was found to be the major component of variation among crosses. For hard wheats, both IP and NP of partial resistance had significant GCA effects, but none had significant specific combining ability (SCA) effects. The results from soft wheat also indicated that GCA was more important than SCA in the inheritance of resistance to SNB. Two hard wheat parents, TX84V344 and SWM14240, and one soft wheat parent, 18NT should he very useful as SNB‐resistant breeding lines.

Resistance to multiple leaf spot diseases in wheat

“…Some previous findings (Duguid and Brûlé-Babel 2001;Singh et al 2006) differed from our results because most wheat genotypes susceptible to the fungus were sensitive to the Ptr ToxA. Although resistance to SNB has been reported to be controlled by multiple genes (Bostwick et al 1993;Du et al 1999;Fried and Meister 1987;Liu et al 2004;Scott et al 1982) or by single genes (Ma and Hughes 1995;Murphy et al 2000), resistance breeding that combines seedling stage resistance and adult plant resistance has been suggested to be more durable to SNB (Krupinsky et al 1972). Our study was conducted to evaluate artificially-inoculated seedling stage in the greenhouse.…”

A quantitative trait locus on chromosome 5B controls resistance of Triticum turgidum (L.) var. diccocoides to Stagonospora nodorum blotch

“…Several genetic studies have shown resistance to SNB to be controlled by multiple genes (Bostwick et al 1993;Du et al 1999;Wicki et al 1999a). Liu et al (2004a, b) reported a major QTL accounting for 58% of the phenotypic variation in the ITMI mapping population.…”

“…The majority of genetic studies (Bostwick et al 1993;Du et al 1999;Ecker et al 1989;Fried and Meister 1987;Nelson and Gates 1980;Scott et al 1982;Wicki et al 1999b) reported that the genetic basis of resistance to SNB in wheat is quantitatively inherited. Resistance loci against SNB were mapped on 16 of the 21 wheat chromosomes (Nicholson et al 1993;Hu et al 1996;Liu et al 2004bLiu et al , 2006Xu et al 2004).…”

Genetic Combining Ability of Petal Shape in Garden Pansy (Viola × wittrockiana Gams) based on Image Analysis

“…To establish effective F 1 hybrid breeding programs, genetic information such as the combining abilities and heritabilities of important plant characteristics must be known. Although numerous analyses of combining ability have been reported for important agronomic traits such as yield (Rainey & Griffiths, 2005) and disease resistance (Du et al, 1999) in edible crops, few studies have investigated the combining abilities of flower appearance characteristics in floricultural crops, with the exception of flower longevity (Van der Meulen-Muisers et al, 1999;Krahl & Randle, 1999).…”