Determination of optimum on-farm seed priming time for maize (Zea mays L) and -Sorghum (Sorghum bicolor [L.] Moench) for use to improve stand establishment in semi-arid agriculture

Abstract

Observations and surveys in semi-arid smallholder agriculture in Zimbabwe suggest that stand establishment of many crops is often extremely poor and is the major cause of low yields. 'On-farm' seed priming experiments were conducted in pots to identify the optimum priming time and compare rate of emergence and early growth of primed and nonprimed seed. Soil mixed with sand in a 1: 1 ratio was filled into pots. Pots were watered to field capacity on the evening prior to sowing and left overnight. Seed of maize (cv. R201 and PAN6363) and sorghum (cv. Red Swazi and Muchayeni) was soaked in water for 0,8, 10, 12, 14, 16, 18,20, 22 and 24 hours. Soaking time was staggered so that all soaking durations terminated at the same time. At the end of priming time seed was removed from water, surface dried and samples of 10 and 24 maize and sorghum seeds, respectively, were sown into each pot. Seedling emergence was assessed on all priming durations in maize and on 0, 8 and 10 h in sorghum because over 50% sprouted before sowing in longer priming times. Early seedling growth was assessed at 14 days after sowing using three seedlings from each treatment. This study provided safe limits, that is, the maximum length of time for which maize 24 h and sorghum seed 10 h should be primed, which if exceeded could lead to seed or seedling damage. These were up to 24 h for maize varieties and 1 0 h for sorghum varieties. Soaking seed of sorghum varieties for 12 h or more caused pre-sowing germination, suggesting that the seed could be susceptible to damage during sowing operations. Time taken for 50% of the seed sown to emerge decreased as priming durations increased from 0 to 10 h in sorghum and 0 to 24 h in 111aize and was reduced by 20 and 23% by soaking for 24 hand 10 h in maize and sorghum, respectively. Both emergence and early growth at 14 days after sowing were improved by soaking. This response of sorghum and maize seed to on-farm priming is an important development which can be used to improve crop stand establishment and early growth in semi-arid agriculture.

Keywords: semi-arid: crop establishment; sorghum; maize: on-farm seed priming; Zimbapwe

Tanzania J. Agric. Sc. (2000) Vol. No., 2, 103-112