Effect of sowing distances on edible pod yields and yield components of three vegetable cowpea cultivars (Vigna unguiculata L. Walp.) Sesquipedalis subspecies, grown in Northeast Thailand.

Abstract

This experiment was conducted at the Experimental Farm, Mahasarakham University, Mahasarakham 44000, Northeast Thailand in the 2006 (August to October) to investigate effect of sowing distances on edible pod yields and yield components of three vegetable cowpea cultivars (Vigna unguiculata L. Walp.) Sesquipedalis subspecies. The experiment was laid in a split plot arranged in a Randomize Complete Block Design with four replications. Five sowing distances were used as main plots (50x10, 50x20, 50x30, 50x40 and 50x50 cm between rows and within rows, respectively) and three cowpea cultivars were used as subplots (MSU 1, KKU 40 and SNU 1). The results showed that there were no statistical differences due to cultivars on total dry weight ha(-1), number of branches plant(-1), marketable pods ha(-1), 100-seed weight and total fresh weight of pods ha(-1) where in most cases genetic potential of the three cultivars were similar. Number of off standard pods was significantly highest with KKU 40 (6.13 pods plant(-1)), whilst MSU 1 and SNU 1 cultivars gave smaller values but both were similar (4.80 and 4.53 pods plant(-1), respectively). The closest sowing distances (T1) gave significantly higher total dry weight ha(-1) and number of off standard pods plant(-1) than other treatments (T2-T5). An increase in sowing distances significantly increased number of branches plant(-1) up to T2 but T2 was similar to other higher sowing distances (T3-T5). Total marketable pods (12,196.50 kg ha(-1)) and total fresh weight of edible pods (12,588.88 kg ha(-1)) were significantly highest with T3 where T3 was the most suitable sowing distances for either of the three cowpea cultivars (50x30 cm between rows and within rows, respectively).