Increasing production and quality of true shallot seed (TSS) using BAP, boron, and insect pollinators

Abstract

True shallot seed (TSS) is one potential alternative of seed source to be developed and be able to solve the problem of shallot seed in Indonesia. Constraints in TSS production are the low flowering and seed formation. Such attempts to improve TSS production is through increasing flowering using benzylaminopurine (BAP), pollen viability using boron and pollination using insect pollinators. The aims of the research were to enhance flowering, pollen viability, TSS production and quality using BAP and boron, as well as study mating system in TSS production and enhance TSS production and quality using insect pollinators. The study consisted of three experiments and was conducted in two location i.e. Lembang (high land - 1250 m asl) during August 2011-August 2012 and in Subang (low land - 100 m asl) during March-August 2012. In each location the experiment was carried out in two steps. In the first step BAP at 0, 50, 100, 150, and 200 ppm and boron at 0, 1, 2, 3, 4 kg ha-1 were used and arranged in randomized block design with three replicates. In the second step there were two trials, namely experiments using self-pollination and cross-pollination, as well as experiments using insect pollinators i.e. bees (Apis mellifera, Apis cerana, Trigona sp.) and green fly (Lucilia sp. - Calliphoridae) were employed, with open pollination as control were arranged in a randomized block design and replicated five times. The results showed that BAP increased flowering, pollen viability and TSS production in Lembang. While boron 1-4 kg ha-1 increased flowering, pollen viability, TSS production and quality in Lembang. The optimum concentration of BAP and dosage of boron for TSS production in Lembang were 37.5 ppm and 2.9 kg/ha respectively. In Subang, BAP enhanced flowering and pollen viability. BAP did not increase the TSS production and quality. Boron also did not affect flowering, pollen viability, TSS production and quality in Subang. Crosspollination was better in producing the yield and quality of TSS than self-pollination in Lembang, but in Subang resulted in lower germination. Honeybee Apis cerana was the most effective pollinator in increasing the yield and quality of TSS both in Lembang and Subang. Increasing production of TSS by A .cerana was 56.8% with 77% germination in Lembang, while in Subang that was 61.3% with 83% germination.