Effect of varieties and sowing time on potato under poplar based agroforestry system

Abstract

Potato crop has a wide flexibility in planting and harvesting, thus it needs standardization of cultural practices under agroforestry for maximizing productivity. Planting time of potato (Solanum tuberosum) varieties was standardized under a block plantation of poplar (Populus deltoides Bartr.) spaced at 5 m x 4 m. Treatments included early, mid and late sown potato varieties viz., Kufri Pukhraj, Kufri Jyoti and Kufri Badshah and five planting times viz., early-November, mid-November, late-November, mid-January and early-February. The best combination of sowing time and variety under block plantation of poplar was late-November sown Kufri Badshah, which produced highest tubers 10 plant^-1, maximum yield 426.4 g plant^-1 and maximum total tuber yield of 18.33 t ha^{- 1}. The tuber yield reduction under poplar plantation compared to open conditions was 6.2% in Kufri Badshah and 11.5% in Kufri Pukhraj when sown during late-November. However, maximum starch content of tubers was observed in Kufri Pukhraj (61.87 mg g^-1) and amongst the sowing times maximum starch content was observed in crop sown during mid November (77.17 mg g^-1). The mid-January and early-February crops gave lower yield due to poor tuber formation as the tuber growth ceases at temperature above 30 ^oC. The tuber yield (g plant^-1) and starch content (mg g ^-1) of potato crop grown under poplar plantation (113.70 and 55.34) was significantly less compared to crop sown under open conditions (151.50 and 88.45).