Effect of prohexadione calcium on vegetative growth, seed maturity and seed yield of the Kabuli chickpea cultivar CDC Frontier

In the western Canadian semi-arid prairies, chickpea maturity is often delayed by the presence of cool and wet, growing conditions, particularly during the late growth stages of the crop. This results in reduced seed yield and quality, by increasing vegetative growth and delaying seed maturity. A field study was conducted in 2010 and 2011 at Brooks and Bow Island in Alberta to evaluate the potential use of prohexadione calcium (PC) to control secondary vegetative growth of Kabuli chickpea cultivar CDC Frontier. PC was foliar-applied at 750, 1500, 3000 and 4500 mg (a.i.) L-1 to CDC Frontier chickpeas at 10, 20 and 30 d after first flower appearance. Results indicated that PC had no significant impact on plant height at the late reproductive stages, mainly due to the resumption of crop growth 2 to 3 wk after the PC treatment; PC decreased seed yield significantly without affecting the green and immature portions. Increasing concentration of PC significantly increased 1000-seed weight only in 2011. In summary, our results suggest that PC treatment at reproductive phase is not a reliable option for controlling excessive crop growth, synchronising seed maturity or improving productivity of chickpea cultivar CDC Frontier in southern Alberta.