Development of Testing Method of Papaya (Carica papaya L.) seed behaviour through studies on seed dormancy, desication tolerance and low temperature

Abstract

Papaya (Carica papaya. L.) seeds are generally classified as intermediate because of it’s sensitive to desiccation until the moisture content below of 10%. It will loss germination when stored at low temperature, but several research determined papaya seed as ortodox. This research aimed to develop detection method of papaya seed behavior through 1) study on seed dormancy and its treatments, 2) study on papaya seeds tolerance to desiccation and 3) study on papaya seeds tolerance to low temperatures. The experiment was conducted at Leuwikopo Experimental Station and Laboratory of Seed Science and Technology of Bogor Agricultura University, and Sumani Experimental Station, Research Centre on Topical Fruit, Solok, West Sumatera from, December 2011 to September 2012. The first experiment separately compiled based on six genotypes of papayas are tested using the Split Plot in randomized complete Design. The first factor is the retention time (0,2,4,6,8 weeks) as the main plot and the second was the seed treatment (dry seeds, soaking with water, heat shock and treatment GA3) as the subplot. A second experiment using Split Plot in Complete Randomized Design. The first factor is the variety /genotype of papaya (Sukma, Merah Delima, Dampit varieties, and 1x2, 6x9 1xD) as the main plot, and each treatment was replicated four times. The second factor is the moisture content (4- 6%, 8-10% and 11-13%) as the subplot. The third experiment seed storage at low temperatures with water content (4-6%) using a completely randomized design (CRD) using those genotypes. The results showed that there were no dormancy on all genotypes tested. The effects of desiccation showed that six genotypes tested were tolerance to low moisture content (MC 4-6 %) with a maximum growth potential > 89% and 88.5%. It showed that Merah Delima and 1x2 genotypes were tolerance to low temperature (-20 °C) with germination percentage range between 79-85%, so that both genotypes classified as orthodox and the others (Sukma, Dampit, 1xD and 6x9 genotypes) classified as intermediate because germination percentage less than 60 %. Based on information of seed dormancy, desiccation tolerance to 4-6% moisture content and low temparature tolerance (-20 °C for 2 days), we can develop method to detect papaya seed behaviour and classified it as intermediate or orthodox.