Post Flowering Stalk Rot Complex of Maize - Present Status and Future Prospects

Post flowering stalk rot complex is one of the most serious, destructive and widespread group of diseases in maize and yield losses range from 10 to 42% and can be as high as 100% in some areas. PFSR nature is often complex as a number of fungi (like Fusarium verticillioides cause Fusarium stalk rot, Macrophomina phaseolina cause charcoal rot, Harpophora maydis cause late wilt) are involved in causation of the diseases. To combat this problem, identification of quantitative trait loci for resistance to PFSR would facilitate the development of disease resistant maize hybrids. Moreover, various chemical and biological control methods have been developed but ma¬jor emphasis is on development of maize cultivars with genetic resistance to for environment friendly control of the Post flowering stalk rot complex. The current paper reviews the information on distribution, impact of the disease, symptoms, epidemiology, disease cycle; genetics of resistance and integrated disease management approaches has been enumerated to understand the present status of knowledge about PFSR complex and will try to focus on the future perspectives available to improve PFSR management

Multi-environment field testing to identify stable sources of resistance to charcoal rot (Macrophomina phaseolina) disease in tropical maize germplasm

The charcoal rot caused by Macrophomina phaseolina is the devastating component of post flowering stalk rot (PFSR) complex which may cause 25 to 32 % yield loss in maize. Therefore for the first time, the study was carried out with multi-environments screening of 137 inbreds at three and 48 maize hybrids at six environments under artificially created epiphytotics at hot-spot locations to identify stable sources of charcoal rot resistance in Indian maize germplasm. Analysis of variance revealed strong effect of genotype by environment interaction on disease response and therefore indicated its complex nature. The mean disease score was ranging from 2.37 to 7.20 in inbreds, and 3.63 to 6.08 in hybrids. Additive main effects and multiplicative Interactions (AMMI) analysis could identifed, DQL1020, DML339, DML1, DQL1019, CM117-1-1 in inbreds and A-7501, CMH08-287, CMH08-292, BIO-562, and CMH08-350 in hybrids as stable sources of charcoal rot resistance. Each testing site viz., Ludhiana, Hyderabad and Delhi was identified as a separate test environment for screening against charcoal rot disease in India. In this study, AMMI model offers a good tool to assess the stability of genotypes and GGE biplot found an efficient tool to identify the mega environments in multi-environment testing. The identified sources of resistance in inbreds can be used in resistant breeding and hybrids can be recommended for cultivation in charcoal rot disease prone area

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Not AvailablePost flowering stalk rot complex is one of the most serious, destructive and widespread group of diseases in maize and yield losses range from 10 to 42% and can be as high as 100% in some areas. PFSR nature is often complex as a number of fungi (like Fusarium verticillioides cause Fusarium stalk rot, Macrophomina phaseolina cause charcoal rot, Harpophora maydis cause late wilt) are involved in causation of the diseases. To combat this problem, identification of quantitative trait loci for resistance to PFSR would facilitate the development of disease resistant maize hybrids. Moreover, various chemical and biological control methods have been developed but major emphasis is on development of maize cultivars with genetic resistance to for environment friendly control of the Post flowering stalk rot complex. The current paper reviews the information on distribution, impact of the disease, symptoms, epidemiology, disease cycle; genetics of resistance and integrated disease management approaches has been enumerated to understand the present status of knowledge about PFSR complex and will try to focus on the future perspectives available to improve PFSR managementNot Availabl

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Not AvailableFrench bean (Phaseolus vulgaris L.) is an important vegetable known as green beans, which is widely cultivated during winter in the subtropics and early spring to fall in temperate zones throughout the world. In India, it is grown in the foothills to higher hills (northwestern Himalayan regions) and North Indian plains (subtropical zone) in different seasons of the year. In India, the French bean breeding program was strengthened with the commencement of the All India Coordinated Research Project on Vegetable Crops (AICRP-VC) in 1971. Only a few bushtype cultivars such as VL Bauni Bean 1, Arka Komal, Contender, and Pant Anupama have been released through AICRP-VC for cultivation in Agro-ecological Zones I (temperate zone) of India (Rai et al., 2004). Because of the dwarf plant habit, short duration, and quality pods, ‘Contender’ has been widely cultivated by the Indian farmers of northwestern Himalayan states (Uttarakhand, Himachal Pradesh, Jammu, and Kashmir). Hence, in this article, we report the release of ‘VL Bean 2’, a cultivar with high green pod yield and better horticultural traits such as pod color, shape, and length as compared with those of current cultivars, including ‘Contender’, available to Indian farmers. This cultivar may be adapted to other temperate regions of the world having similar climatic conditions.Not Availabl

Fungal Species Causing Maize Leaf Blight in Different Agro-Ecologies in India

Foliar diseases of maize cause severe economic losses in India and around the world. The increasing severity of maize leaf blight (MLB) over the past ten years necessitates rigorous identification and characterization of MLB-causing pathogens from different maize production zones to ensure the success of resistance breeding programs and the selection of appropriate disease management strategies. Although Bipolaris maydis is the primary pathogen causing MLB in India, other related genera such as Curvularia, Drechslera, and Exserohilum, and a taxonomically distant genus, Alternaria, are known to infect maize in other countries. To investigate the diversity of pathogens associated with MLB in India, 350 symptomatic leaf samples were collected between 2016 and 2018, from 20 MLB hotspots in nine states representing six ecological zones where maize is grown in India. Twenty representative fungal isolates causing MLB symptoms were characterized based on cultural, pathogenic, and molecular variability. Internal Transcribed Spacer (ITS) and glyceraldehyde-3-phosphate dehydrogenase (GADPH) gene sequence-based phylogenies showed that the majority of isolates (13/20) were Bipolaris maydis. There were also two Curvularia papendorfii isolates, and one isolate each of Bipolaris zeicola, Curvularia siddiquii, Curvularia sporobolicola, an unknown Curvularia sp. isolate phylogenetically close to C. graminicola, and an Alternaria sp. isolate. The B. zeicola, the aforesaid four Curvularia species, and the Alternaria sp. are the first reports of these fungi causing MLB in India. Pathogenicity tests on maize plants showed that isolates identified as Curvularia spp. and Alternaria sp. generally caused more severe MLB symptoms than those identified as Bipolaris spp. The diversity of fungi causing MLB, types of lesions, and variation in disease severity by different isolates described in this study provide baseline information for further investigations on MLB disease distribution, diagnosis, and management in India

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Not AvailableThe charcoal rot caused by Macrophomina phaseolina is the devastating component of post flowering stalk rot (PFSR) complex which may cause 25 to 32 % yield loss in maize. Therefore for the first time, the study was carried out with multi-environments screening of 137 inbreds at three and 48 maize hybrids at six environments under artificially created epiphytotics at hot-spot locations to identify stable sources of charcoal rot resistance in Indian maize germplasm. Analysis of variance revealed strong effect of genotype by environment interaction on disease response and therefore indicated its complex nature. The mean disease score was ranging from 2.37 to 7.20 in inbreds, and 3.63 to 6.08 in hybrids. Additive main effects and multiplicative Interactions (AMMI) analysis could identifed, DQL1020, DML339, DML1, DQL1019, CM117-1-1 in inbreds and A-7501, CMH08-287, CMH08-292, BIO-562, and CMH08-350 in hybrids as stable sources of charcoal rot resistance. Each testing site viz., Ludhiana, Hyderabad and Delhi was identified as a separate test environment for screening against charcoal rot disease in India. In this study, AMMI model offers a good tool to assess the stability of genotypes and GGE biplot found an efficient tool to identify the mega environments in multi-environment testing. The identified sources of resistance in inbreds can be used in resistant breeding and hybrids can be recommended for cultivation in charcoal rot disease prone area.Not Availabl