Effect of sowing time and plant density on growth and seed yield of two guar ecotypes (Cyamopsis tetragonoloba L.)

To evaluate the growth duration and seed yield of two different Guar ecotypes in response to planting time and plant density, a field experiment was conducted in 2016 growing season at the research field of Tarbiat Modares University, Iran. Experimantal factors were arranged as split plot-factorial in a randomized complete block design with three replications. The experimental factors included four planting dates (21 May, 4 June, 21 June and 5 July) assigned to main plots, and factorial combination of three plant densities (130, 200 and 400 thousand plants.ha-1) and two Guar ecotypes (Pakistani and Indian) as sub-plots. The results showed that maximum seed yield (3004.8 kg.ha-1) was obtained from 21 May sowing date and plant density of 130 thousand plants ha-1, while in 4 June sowing date, the highest seed yield was harvested from plant density of 200 thousand plants.ha-1 (1834.4 kg.ha-1). There was significant difference for grain yiled between ecotypes in 21 May and 5 June sowing dates. Pakistani ecotype produced highest highest seed yield (2706.1 kg.ha-1) in 21 May sowing date. In the second sowing date (4 June), the Pakistani ecotype produced 32.1% grain yield more than the Indian ecotype. Pakistani ecotype was superior for seed endosperm percentage (40.5%) as compared to the Indian ecotype (38.8%). In conclusion, sowing of Pakistani ecotype on 21 May with plant density of 130 thousand plants.ha-1 had higher seed yield, longer growing duration, taller plant height, higher 1000-seed weight, higher pod number per square meter, dry matter and harvest index. Therefore, it could be suitable for climatic conditions similar to Karaj in Iran.