1Department of Genetics and Plant Breeding, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi 221005, India
2Department of Mycology and Plant Pathology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi 221005, India
3Crop Improvement Division Central Rice Research Institute, Cuttack 756004, India
4Institute of Agricultural Sciences, Rajeev Gandhi South Campus (RGSC), Banaras Hindu University, Barkachha, Varanasi 221005, India
*Corresponding author: ravi_piyush@rediffmail.com
Online published on 9 January, 2015.
The mode of inheritance of resistance to Xanthomonas oryzae pv. oryzae strain BXO1 and BX043 wild type of bacterial leaf blight disease of rice was studied in six generations of crosses of cultivars HUR 4–3 into PB-1460. The resistance cultivars PB-1460 showed 4.54% disease severity, while susceptible cultivar HUR 4–3 showed 53.01% disease severity against Xanthomonas oryzae pv. oryzae. The area under the disease progress curve (AUDPC) of resistance cultivar was 65.61 which are significantly less than the susceptible cultivar 649.90. The F1 plants were observed to be resistant with an average disease severity 08.87% and AUDPC 110.26. The F2 populations were classified in to four distinct classes on their genotypic ratio of 9:3:3:1 and phenotypically these populations were grouped in two distinct classes resistant and susceptible with their ratio of 13:3, respectively. However, B1 and B2 populations were classified in to two distinct classes as resistant (Resistant/moderately resistant) and susceptible (moderately susceptible/susceptible) in the ratio of genotypic 1:1:1:1 and 1:1 and phenotypically 1:1 and 1:0, respectively. The disease resistance occurs in the population is mainly due to cumulative effects of dominant and recessive two resistant genes i.e., Xa21 and xa13. Chi-square analysis of the population was confirm the inheritance of resistance with their value are 1.24 and 0.66 indicating that the observed data are in line with expected ratio and follow Mendelian pattern of inheritance of resistance to bacterial leaf blight in B1 and B2 generations and modification in the Mendelian ratio of inheritance in the F2 populations, it showed inhibitory gene action i.e., 13:3 that means dominant gene have cumulative effect of recessive gene.
Two popular rice cultivars viz., HUR 4–3 and PB-1460 were used to study the inheritance of resistance for bacterial leaf blight disease.
Disease resistance is governed by the synergistic effect of one dominant Xa21 and one recessive gene xa13, and dominant gene has higher effect than the recessive gene.
The resistance and susceptible reaction were observed in the progenies and it segregates in the ratio of 13: 3 (Inhibitory gene action) in F2, 1: 1 (test cross ratio) in B1 and 1: 0 in B2 generation.
Bacterial leaf blight, disease severity, inheritance, inhibitory gene action, AUDPC
