http://localhost:8080/handle/123456789/2647 Sat, 18 Apr 2026 16:16:06 GMT 2026-04-18T16:16:06Z http://localhost:8080/handle/123456789/3650 GENETIC ANALYSIS OF YIELD AND ITS COMPONENTS IN Brassica rapa L. Ali, Md. Akkas ABSTRACT The experiments were carried out at Sher-e-Bangla Agricultural University from October, 2010 to March, 2013 to perform genetic analysis of yield and its components of Brassica rapa genotypes generated through half diallel crosses and back crossing. No parent showed significant positive gca for yield per plant. SAU Sarisha 2 and SAU Sarisha 3 showed significant negative gca for days to maturity. In case of hybrids, the lowest days to the maturity of 79.33 days was observed in SAU Sarisha 3 × TORI 7. The highest yield per plant and 1000 seed weight were observed in the hybrids BARI Sarisha 6 × SAU Sarisha 2 and BARI Sarisha 6 × SAU Sarisha 1 respectively. The life span of the parent SAU Sarisha 3 was the lowest but the yield was moderate in comparism to other parents. The highest yield and 1000-seed weight were noticed in TORI 7 and its 80% maturity was achieved in 81 days. No hybrid showed significant higher yield over better parent. Three hybrids showed significant negative heterosis for days to maturity. Significant additive and dominant, additive × additive, additive × dominant and dominant × dominant gene interaction were present in Tori 7 × SAU Sarisha 2, SAU Sarisha 1 × SAU Sarisha 2, and SAU Sarisha 2 × SAU Sarisha 3.For numbers of siliqua per plant, number of seed per siliqua and length of siliqua, Vr-Wr graph indicated over dominance gene action for controlling these traits. However, partial dominance gene action was found for controlling the yield per plant. The D and H components were significant for all the traits under study suggesting the importance of both additive and dominance components for the inheritance of all the traits in B. rapa. The ratios of H2/4H1 provide an estimate of the average frequency of positive and negative alleles in all the parents. Regression line intersected the Wr-axis below the origin for all the characters except yield per plant indicating the presence of over dominance. There was no evidence of non-allelic interaction for the character plant height which agreed with the conclusion from individual scaling test results. For the remaining crosses at least one of the two (i and l) interaction parameters were significantly different from zero. The dominance × dominance effects were greater in magnitudes that additive × additive and additive × dominance in all cases which recorded non-allelic interaction in case of plant height. The highest heritability was recorded for days to maturity (99.99%) in the hybrid P1 (TORI 7) × P3 (SAU Sarisha 2). In the cross P1 (TORI 7) × P2 (SAU Sarisha 1), length of siliqua showed high narrow sense heritability (58.06%) with very low genetic gain (0.65). High narrow sense heritability with high genetic gain showed better selection in early segregating generations leading to substantial improvement of the character. In this hybrid P2 (SAU Sarisha 1) × P6 (BARI Sarisha 15 ), yield per plant showed high broad sense heritability but the narrow sense heritability was poor which might be due to presence of non allelic interaction for this character. High values for heritability and genetic advance for various traits indicated good genetic potential for selection. A Thesis submitted to the Faculty of Agriculture, Sher-e-Bangla Agricultural University, Dhaka, in partial fulfilment of the requirements for the degree of DOCTOR OF PHILOSOPHY IN GENETICS AND PLANT BREEDING SEMESTER: JULY- DECEMBER, 2014 Mon, 01 Dec 2014 00:00:00 GMT http://localhost:8080/handle/123456789/3650 2014-12-01T00:00:00Z http://localhost:8080/handle/123456789/2546 GENERATION OF SALT TOLERANT AND HIGH YIELDING GENOTYPES OF GROUNDNUT (Arachis hypogaea L.) THROUGH INTERVARIETAL CROSSES CHOWDHURY, MD. AKRAM HOSSAIN In order to develop salt tolerant and high yielding groundnut genotypes four separate experiments were carried out during the period from August 2010 to January 2014. Of which experiment 1 and 2 were conducted at the net house premises of Sher-e-Bangla Agricultural University (SAU), Dhaka; and experiment 3 and 4 were conducted in the field experimental plot of SAU campus, Dhaka and Agricultural Research Station, Bangladesh Agricultural Research Institute, Benarpota, Satkhira, respectively. To screening the salt tolerant and sensitive genotypes the study was conducted based on sixteen characters of 25 genotypes of groundnut at different salinity levels of 10dS/m, 8dS/m and control tap water 0.38dS/m. From the study it was found that shoot-root characters were reduced with the increase of salinity levels. The yield and yield attributing characters were reduced with the increase of salinity levels. In shoot tissues up take of Na+ and K+ content (%)/plant increased with the increase of salinity, but Ca++ up take increased with the increase of salinity up to 8 dS/m and reduced again with the increase of salinity at 10dS/m level. On the basis of % reduction of shoot biomass, total biomass, pod number, pod yield and kernel yield under salinity six genotypes were selected viz. Binachinabadam-5 as tolerant; Binachinabadam-2 and Binachinabadam-6 as moderately tolerant, BARI Chinabadam-6 and BARI Chinabadam-5 as moderately sensitive and Dhaka-1 as sensitive. To study the combining ability and the nature of gene action the selected seven diverse genotypes were crossed in half diallel fashion and their 21 F1 progenies along with their parents were evaluated in pot culture with saline soil. The significant variation in general and specific combining ability estimated for all the characters were observed which indicated the importance of both additive and non-additive gene actions in inheritance of these characters. The characters are controlled either by additive x dominant or by dominant x dominant type gene interaction and thus non-fixable. Wr-Vr analysis showed absence of nonallelic interaction for the expression of total biomass, pod number, pod yield and kernel weight. The genetic studies of all traits is appeared to be controlled by poly genes (two to five groups) with preponderance of dominance effect and the genes with positive and negative effects followed asymmetrically distribution amongst the parents. Pod yield, kernel weight and pod number had highest, higher and moderate narrow sense heritability respectively. This means simple progeny selection could be effectively followed in the segregating generations for these traits under salinity. The genotypic effects and comparative performance of F2 7x7 diallel population in experiment 3and 4 showed the presence of wide range of variation among the genotypes for all characters in non-saline and saline field condition, respectively. In nonsaline field condition cross P2xP5 showed the highest pod yield per plant followed by cross P4xP6, P5xP7, P5xP6, P1xP7, P4xP7 and P3xP7. In both field conditions, moderate to high estimates of heritability along with high genetic advance in percentage of mean for pod yield and yield contributing traits suggests that improvement of these would be further progressed through selection. The F2 crosses P2xP3, P1xP2, P2xP4, P1xP3, P2xP6 and P2xP5 as the most salt tolerant genotypes could serve as a source of genetic material for the improvement of high yielding salt tolerant varieties in saline field condition. A Thesis submitted to the Faculty of Agriculture, Sher-e-Bangla Agricultural University, Dhaka, in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY IN GENETICS AND PLANT BREEDING SEMESTER: JULY - DECEMBER, 2014 Mon, 01 Dec 2014 00:00:00 GMT http://localhost:8080/handle/123456789/2546 2014-12-01T00:00:00Z