Abstract

Major difficulty of raising papaya seedling is mortality of seedling, among abiotic factors of environment like unfavourable microclimate; especially temperature restricts raising off-season fruit nursery under open field condition in arid region. Papaya (Carica papaya L.) is widely grown fruit crop in tropics and India is the largest producer in the world. Papaya seedlings are fetching very high price during off-season availability. In this study, a low tunnel greenhouse (S1) and black shade net house (S2) were taken as protected structures for growing of papaya seedlings. The variety of papaya seedlings was Madhubindu and soil+FYM was taken as growing media for this study. Survival and growth of seedlings were monitored for 30–60 days. The environmental and morphological data were recorded and computed and response of papaya seedling growth was evaluated in terms of germination percentage, seedling height, collar diameter, number of leaves, diameter of shoot, fresh and dry weight of aboveground and underground biomass, sturdiness, root: shoot ratio, vigour index length andvigour index mass in root media. The results of this study revealed that the environmental factor during the entire study period was found significant in black shade net structure compared to greenhouse. Variation in seedling growth in different microclimatic conditions may be due to the differences in growth behaviour under given set of environmental conditions. The minimum time taken for days of germination, germination percentage, seedling height, collar and shoot diameter was found highest in black shade net house (S2) with variety i. e. Madhubindu and soil+FYM as growing media. Economically black shade net house with net profit 513.27 Rs./m2, BCR 3.94 and payback period 0.59 was found highly suitable for raising seedling of papaya off-seasonally and mitigating climate change in arid region.