Morphometric and qualitative response of onion varieties in Poplar-vegetable based agroforestry system

Abstract

Vegetable-based agroforestry has prompted deep interest, considering the dietary, economic, and multifarious utility of onion (Allium cepa L.) which is an important vegetable crop; the present study was conducted at Punjab Agricultural University, Ludhiana, India for two years, 2018-19 and 2019-20 under split-split plot design. The six onion varieties (POH-1, PRO-6, PRO-7, PWO-2, PYO-1 and Punjab Naroya) were planted in two environments (poplar and open) at three planting times (mid-December, end-December and mid-January). The morphological and qualitative performance of onion varied significantly with transplanting time and amongst the varieties. With the advancement of planting time, the height no. of leaves and neck thickness showed a declining trend. The mid-December planted seedlings shown taller plants (64.69 and 65.18) with maximum leaves (7.41 and 6.08) and neck thickness (1.25 cm and 1.56 cm) followed by end December. Among the six onion varieties, PRO-7 was significantly taller (65.71cm and 61.37cm) with maximum no. of leaves (7.28 and 6.16) and took minimum number of days to bulb initiation (68) and maturity (122). PYO-1 recorded significantly more neck thickness than other varieties but at par with Pb. Naroya. Nevertheless, PWO-2 produced significantly higher mean dry matter content (15.14%) as well as total soluble solids, (13.11%) thus better variety in quality in both the years.  Conversely, the variety PYO-1 performed poorly both in terms of growth and quality (DMC-9.8% and TSS-10.02%) indicating it may not be the most suitable choice for cultivation under poplar. The mean performance of the three planting times showed that maximum DMC was produced in mid-December planted crop and decreased towards mid-January planting time while TSS remained insignificant for transplanting times. Henceforth, variety PWO-2 performed better with poplar for nutritional value while variety PRO-7 has proved better in terms of substantial growth rate.