Diallel analysis of barley for resistance to leaf stripe and impact of the disease on genetic variability for yield components

Abstract

Barley breeders in Syria attempting to develop barley (Hordeum vulgare L.) cultivars resistant to barley leaf stripe (BLS) disease caused by Pyrenophora graminea Ito & Kuribayashi [anamorph Drechslera graminea (Rabenh. Ex. Schlech. Shoem.)]. Information on the combining ability for BLS resistance in Syria is not available. This study was conducted to evaluate, in 10 genetically diverse barley parents, general combining ability (GCA) and specific combining ability (SCA) effects towards the determination of the genetic basis of disease resistance and to estimate genetic variability for yield components and its modification by BLS. Ten parental genotypes varying in their reactions to BLS were crossed in a half-diallel mating design to generate 45 full-sib families. The families and the parents were inoculated with P. graminea and evaluated for resistance in replicated field tests (three inoculated and three non-inoculated plots). The parents chosen showed wide variations for resistance to BLS. Genetic component analysis showed significant effects for both GCA and SCA for resistance to BLS, suggesting that additive as well as non-additive genetic mechanisms were involved in the expression of resistance in these parents. GCA effects were more important than SCA effects. Resistant parents exhibited high negative GCA indicating that additive gene effects were more predominant, and suggesting their prime suitability for use in barley breeding programs to improve resistance to BLS. Narrow-sense heritability was 58% and broad-sense heritability was 99% indicating that selection for BLS resistance should be effective in these crosses. A high genetic variability for the agronomic traits studied was observed. Yield components decreased significantly in inoculated plants and more pronounced in diseased plants. Significant GCA was observed for all traits. Values for GCA were, in some cases, significantly modified by BLS. This indicates that attention must be paid to the danger of drawing conclusion in quantitative genetics studies dealing with both diseased and healthy plants. Two genotypes, Banteng and Igri, had high negative GCA effects and are promising parents for enhancement of BLS resistance.

Combining ability analysis for yield traits in barley (Hordeum vulgare L.)

“…Katiyar et al effects in desirable direction for any trait. These findings are in congruence with results obtained byZeng and Chen (2001);Singh et al (2005);Arabi(2005) andSayed et al (2008).…”

Deciphering the transcriptional regulation and spatiotemporal distribution of immunity response in barley to Pyrenophora graminea fungal invasion

“…Studies were carried out by comparison of two varieties/genotypes of barley Banteng and Fourat-1. The variety Banteng was previously demonstrated to have some resistance qualities to all Pg isolates originated and isolated from Syrian barley fields [ 7 , 8 ]. Fourat-1 is a universal susceptible variety for all Syrian isolates.…”

“…In a previously described monoconidial isolates collection, the Pg-Sy3 isolate was the most virulent of isolates collected between 2000 and 2002 from naturally infected barley in different regions of Syria [ 7 , 8 ]. The fungal mycelia were transferred from a stock culture into Petri dishes containing potato dextrose agar (PDA, DIFCO, Detroit, MI, USA) supplemented with 13 mg/l kanamycin sulfate and incubated for 10 days at 20° ± 1 °C in the dark.…”

“…Rdg2a gene, turned out to encode a protein of the CC-NB-LRR type, which confers immunity toward the Pg -isolate Dg2 without the establishment of a hypersensitive response (HR) [ 17 ]. Remarkably, numerous genotypes of barley display a resistant phenotype without HR, resulting in partial or quantitative resistance [ 7 , 12 ]. So far, little is known about the genetic variability/background and the mechanisms underlying the barley-fungus interactions in pathosystems other than Dg2-Rdg2 .…”

High Heritability in a Resistant Barley Genetic Source to Spot Blotch (Cochliobolus sativus)

“…Furthermore, the cv. Banteng was resistant to net blotch, barley stripe (Arabi, 2005b) and powdery mildew (Arabi and Jawhar, 2012), which could give it special interest in barley breeding programmes.…”