Studies on Seed Size and Storage on Germinability and Performance of young Jojoba (Simmondsia Chinensis L.) Seedlings in Semi-arid Areas of Kenya

Abstract

Jojoba (Simmondsia chinesis L.) is a highly valued desert shrub for its oil which is equivalent to that of Sperm Whale, a threatened species by extinction. Cultivation of Jojoba in arid areas means provision of a cash-crop, environmental conservation and preservation of the Whale. Its seeds vary in size depending on genotype, season and seed lot. An experiment was setup in September 2012 with an objective of characterizing seed and determining the effect of size and storage on germination. The experiment was laid down in a Completely Randomized Design (CRD) with three treatments replicated thrice for the first two experiments. However, the third experiment was a factorial one with eight treatments. The seeds were grouped into three categories which were large (1,047 mg), medium (697 mg) and small (333 mg/seed). The results revealed that large seeds had significantly (P< 0.05) higher germination percentage (76%) compared with medium (33%) and small (37%) seeds. Large seeds were found to contain large cotyledon size. Large cotyledons provide a large food reserve which is essential for germination and early vigorous growth. Seed length and 100 seed weight were significantly (P≤0.05) higher for large seed as compared to medium and small seeds. Similarly, large seeds recorded a germination of 93% for a short storage of six months which was superior to that of small seeds which was 17% for the same period. Hence seed length and 100 seed weight were found to be reliable variables for characterizing Jojoba seeds which may be used in predicting germinability. We recommended that for enhanced germination and vigorous growth of seedlings, it is necessary to select and plant large Jojoba seeds which have been stored for period less than one year.