Browsing by Author "Lal C. Prasad"

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A new technique for monoconidial culture of the most aggressive isolate in a given population of Bipolaris sorokiniana, cause of foliar spot blotch in wheat and barley
(2007) Dharmendra Kumar; Ramesh Chand; Lal C. Prasad; Arun K. Joshi
We developed a new technique for monoconidial culture of the most aggressive isolate in a given population of Bipolaris sorokiniana, to facilitate the evaluation of spot blotch resistance in wheat and barley. Blotched portions of infected barley leaves were placed on a glass slide in a moist chamber for production of conidia by associated fungal hyphae. Conidia were collected separately and grown on water agar discs. Individual water agar discs having conidium growth were inoculated on barley leaves. The conidium producing the earliest symptom with the largest lesion was considered most aggressive. This lesion was incubated in a moist chamber and the conidial offspring were tested for pathogenicity. When a uniform infection was observed, a small piece of the lesion was cut using a sterilized scalpel, surface sterilized with NaOCl, and inoculated in the centre of Petri dishes containing potato dextrose agar medium. The inoculated Petri dishes were incubated at 25 ± 1°C to yield monoconidial cultures of the most aggressive isolate. Variability in symptom expression caused by the most aggressive isolate of a given population was much less than variability in symptom expression caused by all isolates collectively. The techniques will be useful for plant pathologists and breeders in screening for spot blotch resistance in wheat and barley. © 2007 Springer Science+Business Media B.V.
Combining ability analysis for grain filling duration and yield traits in spring wheat (Triticum aestivum L. em. Thell.)
(Brazilian Journal of Genetics, 2007) Kamaluddin; Rishi M. Singh; Lal C. Prasad; Malik Z. Abdin; Arun K. Joshi
A diallel analysis of wheat (Triticum aestivum L. em. Thell) parents (n = 11) and their F1 (n = 55) and F2 (n = 55) offspring was carried out for the following four traits: grain filling duration (GFD), GFD for growing degree days (GDD), 1000 seed weight and seed yield per plant. Analysis of variance for general combining ability (GCA) and specific combining ability (SCA) displayed significant F1 and F2 general and specific combining ability effects for the four traits studied. For all the traits the GCA effects were relatively more important than the SCA effects, indicating that additive genetic effects were predominant. Crosses displaying high SCA effects for grain filling duration, seed weight and yield were observed to be derived from parents having various types of GCA effects (high x high, high x low, low x low and medium x low). The single seed descent method can be applied to exploit additive gene effects whereas dominance gene effects could be valuable in hybrid wheat breeding programs. Among the parents, genotypes from the International Maize and Wheat Improvement Center (Centro Internacional de Mejoramiento de Maíz y Trigo, CIMMYT) as well as South Asia were found to be superior general combiners for grain filling duration. Likewise, crosses involving diverse parents from CIMMYT and South Asia showed significant SCA effects for grain filling duration and other traits. Copyright by the Brazilian Society of Genetics.
Variation for infection response to Bipolaris sorokiniana and identification of trait specific sources in barley (Hordeum vulgare L.) germplasm
(Southern Cross Publishing and Printing Pty Ltd, 2014) Tejveer Singh; Vinod K. Mishra; Lal C. Prasad; Ramesh Chand
The aim of present study was to evaluate un-adapted, exotic and indigenous germplasm of barley to identify useful genetic diversity for spot blotch resistance and other related traits to barley breeders. A total 124 genotypes were evaluated for spot blotch resistance and yield components, for three consecutive years at Varanasi, India. Based on Area Under Disease Progress Curve (AUDPC) score of spot blotch, three germplasm accessions (BCU422, BCU1204 and BCU5092) were found resistant to virulent isolate of spot blotch disease. Trait specific accessions were also identified for yield components traits. To meet breeders' requirements, genetically diverse pairs for specific trait were identified, that can be utilized as parents in breeding programs. Principal Component Analysis (PCA) for AUDPC score and yield components showed that , the first three principal components explained 60.30% (27.22, 18.22 and 14.86% by PC1, PC2 and PC3 respectively) of genetic variation. Identified accessions for spot blotch resistance and yield contributing traits appear to be useful for resistance against Bipolaris sorokiniana and improvement in genetic potential of grain yield by providing desirable gene(s)/QTL(s) in barley genetic improvement programme.