Physiological response of field-grown onion to some growth regulators

摘要

The effect of gibberellic acid (GA3), indole-acetic acid (IAA), indole-butyric acid (IBA) and (#alpha#-naphthalene-acetic acid (NAA) [growth promoters]; and uniconazole (UC) and cycocel (CCC) [growth retardants] on growth, chlorophyll content, nutritional status, and seed yield and quality of onion was investigated. Results revealed significant differences among the studied growth regulators in dry weight per plant, Chl a, Chl a+b, total carbohydrates, mineral contents (N, P and K), scape length, seed yield (per plant and per plot), and seed index (weight of 1000 seeds) and germination. Also, plants treated with GA3 showed the highest value of scape length, while application of NAA induced the highest increase in the other parameters. Moreover, spraying UC enhanced all parameters, except K content and scape length, more than CCC. In contrast, no significant differences were observed in all studied parameters, except K content and percentage of seed germination, under the effect of concentrationswithin substances. In this regard, plants sprayed with 50 ppm of NAA showed the highest seed yield (19.2 g/plant and 860.25 g/plot), seed index (3.8 g) and seed germination (90.9 percent), whereas control plants had the lowest values (15.8 g/plant and 693.75 g/plot), (3.5 g) and (80.9 percent) in the same order.