DEVELOPMENT OF HEALTHY SEED PRODUCTION TECHNOLOGY OF RADISH (RAPHANUS SATIVUS L.)

Abstract

Radish (Raphanus sativus L. var. Tasaki Mula) belonging to the family Cruciferae, the high yielding tropical annual type, developed by the Bangladesh Agricultural Research Institute, was used in the present investigations. In total, 27 seed samples were randomly collected from 27 farmers comprising nine farmers from each of three upzillas viz. Thakurgaon sadar, Birgonj and Kaharol of Dinajpur district for testing their quality and health status. Laboratory studies revealed that all the seed samples were infected with Alternaria at different range of infection (0.5-25.4%), Alternaria brassicae was recorded as the dominant pathogen, where A. brassicicola wok alternata were found minor. The efficacies of four seed treating fungicides (Iprodione, Mancozeb, Carbendazim and Vitavax-200) and one bio-control means (BAU-Biofungicide) were tested for their performance of raising stickling in seed beds. Among the chemicals, Mancozeb was found superior to other fungicides in terms of increasing the field emergence and stickling stand by 53.16% and 65.38%, respectively and lowering post emergence death by 58.91% over non-treated control. BAU-Biofungicide was found statistically at par with Mancozeb where the field emergence and stickling stand were increased by 40.65% and 50.59%, respectively over non-treated control with a decrease of post emergence death by 47.39%. Pathogenicity studies in pots showed that Alternaria brassicae, A. brassicicola and A. alternata were pathogenic to radish plants. But A. brassicae was found as major and_A. brassicicola and A. alternata were minor pathogens. In field studies on foliar spray’ Iprodione (0.25%) followed by Mancozeb (0.3%) provided maximum control of Alternaria blight and increased seed yield. The results in second cropping Season (2005-2006), 10 December (early) transplanting with three sprays of Iprodione resulted lowest leaf area diseased, whereas plants in 25 December (normal) transplanting had the lower pod area diseased. In third cropping season (2006-2007), 25 October transplantation with BAU-Biofungicide (2.0%) and Iprodione (0.25%) foliar application showed significant effect in reducing Alternaria blight and increased seed yield by 120.45% and 97.73%, respectively over non-sprayed control. Bio-Biofungicide ranked second in reducing the disease, but ranked first in increasing seed yield. The cost benefit analysis of management practices for radish seed crop during 2005-2006 revealed that stickling transplanting in 25 December (normal) with two sprays of IprSdione (0.25%) yielded the highest return (BCR 3.27), whereas negative result (BCR -0.89) has been estimated in case of non-sprayed control plots in late transplanting (10 January). But cost benefit analysis of cropping season 2006- 2007 revealed that BAU-Biofungicide (2.0%) six sprays yielded the highest return (BCR 4.41) followed by six sprays of Iprddione (BCR 3.90). Out of the three different storage conditions (dehumidified, BADC storage and farmers house) and four different containers (metal, glass bottle, polythene bag and plastic bottle), maximum germination (95.25%) with lowest (3.00%) infection was recorded in dehumidified conditions in metal container, while lowest germination (71.25%) with highest (6.25%) infection was obtained in case of farmers conditions of plastic bottle. There was increase in starch, reducing sugar, non-reducing sugar and ash in the diseased seed as compared to healthy looking seed but crude protein and crude lipid were decreased in diseased seed as compared to healthy looking seed. Sugar was higher in Alternaria infected seed than the healthy looking seeds of radish variety cv. Tasaki Mula. Finally, it may be concluded that Integration of early transplanting (25 October) with foliar sprays of BAU-Biofungicide (2.0%) was found best for eco-friendly management of Alternaria blight of radish seed crop with significantly higher seed yield.