Use of hydrogen cyanamide to improve flowering and fruit set in nashi (Pyrus serafinaRehd.)

Abstract

Abstract Hydrogen cyanamide use was investigated as a means of improving flowering and fruit set in nashi (Asian pear, Pyrus serotina Rehder var. culta Rehder) cultivars. The onset of flowering and shoot extension were advanced, and the length of the flowering period was shortened in all cultivars tested. Most response was shown by the later-flowering cultivars ‘Shinseiki’ and ‘Nijisseiki’, Best results were achieved at application rates of 3% a.i. Applications of hydrogen cyanamide at 6 and 9% a.i, caused serious bud and wood damage, regardless of time of application. Application at 3% a.i. caused damage only if applied within 3 weeks of natural flowering. At 1.5%, no damage occurred, but the effects on flowering were uneven and the results inconsistent. For the pollinator, ‘Shinseiki’, best results were achieved with a single application of 3% a.i. at c. 30–50 days before natural flowering, substantially improving overlap with the flowering periods of the other nashi cultivars. Early applications were s...