~ 2705 ~ Journal of Pharmacognosy and Phytochemistry 2019; 8(4): 2705-2708 E-ISSN: 2278-4136 P-ISSN: 2349-8234 JPP 2019; 8(4): 2705-2708 Received: 01-05-2019 Accepted: 03-06-2019 HB Virani Department of Genetics and Plant Breeding, College of Agriculture, Junagadh Agricultural University, Junagadh, Gujarat, India RB Madariya Department of Genetics and Plant Breeding, College of Agriculture, Junagadh Agricultural University, Junagadh, Gujarat, India A Panera Department of Genetics and Plant Breeding, College of Agriculture, Junagadh Agricultural University, Junagadh, Gujarat, India NM Bhut Department of Genetics and Plant Breeding, College of Agriculture, Junagadh Agricultural University, Junagadh, Gujarat, India Correspondence HB Virani Department of Genetics and Plant Breeding, College of Agriculture, Junagadh Agricultural University, Junagadh, Gujarat, India Genetic analysis of yield and its biometric traits in castor ( Ricinus communis L.) HB Virani, RB Madariya, A Panera and NM Bhut Abstract The P1, P2, F1, F2, BC1 and BC2 of five castor crosses viz., JM-6 x 48-1, JI-433 x SKI-346, JI-436 x PCS- 124, SKI-346 x JI-35 and SKI-346 x SKI-215 were studied for twelve metric traits. The scaling tests revealed the importance of additive-dominance model for number of nodes up to primary raceme in JI- 436 x PCS-124. The result of rest of the cases depicted the epistatic digenic model including all types of interactions played a major role for the entire cross combinations. The study revealed the importance of additive and non-additive type of gene action for all the characters studied suggesting the use of reciprocal recurrent selection or biparental mating for improving the characters in castor. Duplicate type epistasis played a greater role than complementary epistasis in most of the cases. Keywords: Castor, generation mean analysis; scaling tests, additive, dominance, epistatic gene Introduction Castor (Ricinus communis L.) is grown in tropical, sub-tropical and temperate regions of world. Castor is highly cross pollinated crop and being a sexually polymorphic species with different sex forms viz., monoecious, pistillate and pistillate with interspersed staminate flowers (ISF). The breeding method to be adopted depends mainly on the nature of gene action involved in the expression of the quantitative traits. Line x tester analysis is used to select the parents based on their combining ability but fails to detect the epistasis which remains the most complex problem and on which it is extremely difficult to obtain reliable results. The epistasis can be detected by the analysis of generation means using the scaling tests, whether it is additive x additive, additive x dominance and dominance x dominance type of gene interaction at the digenic level. After confirmation of epistasis, joint scaling test of six parameter model m, (d), (h), (i), (j) and (l) can be applied. Therefore, in this context, the objective of the present study was to obtain information on the gene effects to provide a basis of selection in a breeding programme for the improvement of castor. Material and Methods The experimental material was comprised of five castor crosses viz., JM-6 x 48-1, JI-433 x SKI-346, JI-436 x PCS-124, SKI-346 x JI-35 and SKI-346 x SKI-215, each with six basic generations viz., P 1 , P 2 , F 1 , F 2 , BC 1 and BC 2 . The experiment was laid out in Compact Family Block Design with three replications at Main Oilseeds Research Station, Junagadh Agriculture University, Junagadh (Gujarat). The single row plot was sown for both parents and their F 1 ‘s, four rows for each F 2 generation and two rows for each backcross during Kharif 2018-19. The seed was dibbled with 120 cm and 60 cm as inter and intra row spacing, respectively and with 6 m of row length. All the recommended cultural and plant protection practices were followed to raise good crop. The data were recorded on individual plant basis in each replication on randomly selected five competitive plants in each of parents and F 1 ‘s, 10 plants in each of backcross and 20 plants in F 2 generations for 12 characters. The data were first subjected to estimates of individual scaling tests A, B, C and D of Mather (1949) [5] and joint scaling test of Cavalli (1952) [1] to detect the presence of epistasis. The gene effects were estimated using the models suggested by Jinks and Jones (1958) [4] . The significance of the scales and gene effects were tested by using the t-test (Singh and Chaudhary, 2004) [9] . Results and Discussion The analysis of variance between families revealed that the mean squares due to crosses were significant for all the characters. The analysis of variance revealed significant differences among six basic generation means for all the characters studied in all the five crosses except oil content in JI-433 x SKI-346 (Table 1). This character which failed to show significant variation among the generations was not subjected to further statistical analysis.