Tropical Grasslands (2007) Volume 41, 5560
Effects of ethephon, salicylic acid and cidef-4 on the yield and quality of guinea grass seed
T.B.M. JOAQUÍN1, C. TREJO2, A. HERNÁNDEZ-GARAY3, P.J. PÉREZ3, S DE G. GARCÍA4 AND C.A.R. QUERO3
1 Departamento de Zootecnia, Universidad del
Papaloapan, Loma Bonita, Oaxaca, México
The effect of applying plant growth regulators on seed yield and quality of guinea grass (Panicum maximum) cv. Tanzania was studied in one crop on a sandy clay in Mexico. The treatments consisted of 3 growth regulators [ethephon, salicylic acid and a steroidal phytohormone (cidef-4)], 2 stages of application (before seed head emergence and at the beginning of anthesis) and 4 application concentrations [0, 600, 1200 and 1800 mg/kg active ingredient (a.i.) for ethephon; 0, 10-5, 10-4 and 10-3 M for salicylic acid; and 0, 2, 4 and 6 mg/kg a.i. for cidef-4]. The growth regulators were applied as a spray in water at 850 L/ha. Pure seed yield varied between the growth regulators evaluated (P<0.05), and the greatest yield (179 kg/ha) was obtained using cidef-4. Ethephon greatly reduced seed yields at the highest 2 rates when applied early, mainly through reducing number of heads emerging. Salicylic acid had a beneficial effect on seed yield at the highest application rate, irrespective of when applied. Cidef-4 greatly increased seed yield, irrespective of when applied, with the effect tending to increase with application rate over the full range. It acted primarily through an increase in head density and to a lesser extent head size. Seed quality (1000-seed weight, seed purity and germination %) was not significantly affected by any of the treatments applied.