Judul: Genetic Analysis and Metabolomic Studies of Less Irrigation Tolerance in Chili (Capsicum annuum L.)
Abstrak: Chili is one of the most notable horticultural commodities which have high economic value. However, the national chili production is still low and unstable. This instability in production is due to changes in chili agricultural land area which resulted from land conversion and low plant productivity which caused by changing growing environment conditions. Utilization of dry land for cultivation of chili plants is an alternative that can be chosen to increase chili production. Indonesia has enormous dry land potential, however, annual crop farming and horticulture on dry land, especially outside Java, has low production due to biophysical constraints on land and water deficit. Water deficit is one of the limitations on chili production. An effort can be done to increase chili productivity in dry land is the cultivation of superior varieties which are tolerant to less irrigation. Evaluation of less irrigation tolerance of chili plants to identify the response differences need to be conducted to obtain chili plants that are tolerant to water deficit. Breeding of less irrigation tolerance varieties requires donor parents that have less irrigation tolerance and known information on genetic control of the trait. Understanding the genetic basis of limited water tolerance of plants is a prerequisite for developing superior genotypes. Lack of water generally affects physiological, biochemical, and molecular processes in the form of disruption of metabolite homeostasis and causes significant changes in the chemical composition of plants that require temporal adjustment in the metabolic pathways. Metabolomic analysis of chili genotypes with different tolerance levels can be conducted to investigate important metabolite compounds in chili plants related to limited water. The metabolic profile of chilies, especially in determining the level of limited water tolerance to limited irrigation stress, is essential information in developing limited water tolerant chili plant breeding program. This study is entitled “genetic analysis and metabolomic study of less irrigation tolerance of chili plants”. The study aimed to evaluate the selection environment, select chili plants that are tolerant to less irrigation stress and determine the genetic parameters, the general combining ability (GCA) and the specific combining ability (SCA) of the genotypes used in relation to less irrigation tolerance. An irrigation interval of 7 days or equivalent to 52-58% media water content of field capacity were used to identify differences in response between 23 genotypes of chili to less irrigation in pots. A polietylen glicol (PEG) concentration of 15% or equivalent to osmotic potential of -4.1 Bar were used to identify differences in response between 22 chili genotypes to drought stress during the germination phase. The root shoot ratio character was determined as selection character for less irrigation tolerance during the vegetative phase. Meanwhile, selection characters to estimate the less irrigation tolerance of chili genotypes in the germination phase were the hypocotyl length, root length, ratio of root length to hypocotyl length, sprout length, hypocotyl dry weight, and percentage of germination. The study results showed that there were differences in the level of drought tolerance from the chili genotypes tested. Based on evaluation at vegetative phase showed that IPB C-5, IPB C-7, IPB C-8, IPB C-12, IPB
Keyword: chili, combining ability, drought tolerance, metabolomics