Yield and component yield of onion (Allium cepa L.) effect of salicylic acid under drought stress in Indonesia

Abstract

The use of salicylic acid as a resistance inducer agent in several plant species was well known. Salicylic acid has been believed to play an important role in inducing drought resistance. The use of salicylic acid and dryness in onion (Allium cepa L.) has nev-er been studied. The present study aimed to ascertain how limited water supply and salicylic acid (SA) interact with onion (Allium cepa L. ) yield and component yield traits. A completely randomized design (CRD) and two-factor treatment with three replications were employed in the investigation. Drought was the first factor (FC1(field capacity), FC2 ( at 60% field capacity), FC3 (at 20% field capacity). The concentration of salicylic acid (SA) was the second component (0 mM, 0.5 mM, and 1 mM). The following parameters were measured: relative water content (RWC), water use efficiency (WUE), plant height, number of leaves, number of tillers, root length, chlorophyll content index (CCI), proline, bulb weight (bw), strawweight (w), bulb diameter, bulb production (bp), harvest index (hi), and bulb diameter. The results showed that tillers increased (7.0 to 10.0) as SA concentration increased at three levels of dryness. However, plant height (40.6 to 30.0cm) and the number of leaves (24.3 to 16.0) decreased as drought increased. Dryness in bulb weight, strawweight, bulb diameter, and bulb production could not be alleviat-ed by the SA concentration. Salicylic acid 1 mM has been able to overcome drought up to 20% of field capacity as indicated by plant height and leaf area but was unable to prevent drought on bulb weight and tuber diameter. Thus, the concentration of salicylic acid given would help to overcome drought (water deficit) in shallot plants.