ASSESSING THE COMBINING ABILITY OF RICE GENOTYPES IN F1 GENERATION USING COMPLETE DIALLEL CROSS

Combining ability analysis was studied in an 8 × 8 diallel set of black gram genotypes. Variance due to general combining ability (GCA) among the parents for all the traits, and due to specific combining ability (SCA) among the crosses was deduced. Combining ability analysis is an important tool to find out gene actions and it is frequently used by plant breeder to choose parents with high GCA and hybrids with high SCA effects. GCA is associated with additive genetic effects, whereas SCA is taken as the measure of non-additive type of gene actions, arising largely from dominance and epistatic deviations with respect to certain traits. GCA is attributed to additive and additive gene effects epistasis and is theoretically fixable on the other hand; SCA attributed to non-additive gene action due to dominance or epistasis or both and is non-fixable. The presence of non-additive genetic variance is the primary reason for initiating the hybrid programme. GCA variance (σ 2 gca ) was invariably lower than SCA variance (σ 2 sca ) for almost all characters indicating preponderance of non-additive gene action. The percentage of heritability in broad sense was highest with days to maturity (94.78%) followed by days to 50% flowering (94.67%). The gca effect ranged from -0.16 to 0.25. OBG-31 (0.25) had maximum significant positive gca effect followed by Keonjhar Local (0.24). OBG-17 (-0.16) and TU-94-2 (-0.16) witnessed the maximum negative gca effect for yield/plant followed by B-3-8-8 (-0.14). For yield the range of sca varied from -0.64 to 1.02. Among the 28 F 1 hybrids B-3-8-8 × PU-30 (1.02) had the highest sca effect followed by PU-35 × LBG-17 (0.71) and PU-30 × OBG-31 (0.48) for yield/plant. The mean yield per plant was recorded highest in PU-35 × LBG-17 (6.19) followed by OBG-31 × Keonjhar Local (6.16), LBG-17 × OBG-31 (6.15) and B-3-8-8 × PU-30 (6.14). Among 28 cross combinations 11 crosses exhibited positive sca effect (9 were significant) for this character whereas 17 crosses exhibited negative sca effect (13 were significant).

The goal of the current study to estimate the combining ability and gene effects for grain yield and its attributing traits in Macaroni wheat (Triticum durum Desf.). During Rabi 2023-24, eight lines and four testers were used in an attempt to make crossovers utilizing a line × tester mating scheme. In Rabi 2024–2025, the 32 hybrids that were produced, along with 12 parents and one standard check (GW 1339), were examined at the Wheat Research Station, Junagadh Agricultural University, Junagadh, using a randomized block design with three replications. The analysis of variance for combining ability revealed that the mean square due to lines and testers were significant for all the characters except mean square due to testers for plant height and 100-grain weight. Likewise, mean squares due to line × tester interaction was also found significant for all characters under investigation except plant height. For every individual in the study, the influence of specific gene combinations (SCA) on their traits was more significant than the general influence of their parents (GCA). This was further supported by the ratio of σ2gca/σ2sca was less than unity for all characters confirmed the preponderance of non-additive gene action for all the traits. The estimates of gca effect indicated that among the lines, MACS 3949, GW 1348, MPO 1357 and HD 4758 were found to be good general combiners for grain yield per plant, while GDW 1255 and NIDW 1158 identified as good general combiner for this trait among testers. Parent UAS 475 was found to be good general combiners for early maturity due to negative and significant gca effects for days to anthesis and days to maturity. For grain yield per plant out of 32 crosses 11 were evaluated for their sca effects exhibited significant and favourable sca effects. Among them, the highest sca effects was manifested by the cross GW 1348 × GDW 1255 followed by HD 4758 × WHD 965 and HI 8841 × HI 8737.

Seven rice varieties (Hassani, Deilmani, Sepidruod, Shahpasand, Saleh, Neda and IRFAON215) and their complete diallel progenies were grown in a randomized complete block design with three replications in the growing seasons of 2006 and 2007 at the Rice Research Institute of Iran (RRII) in Rasht. Genetic components, the mode of inheritance and heterosis of various physiological traits were studied by using seven-parent diallel mating design including reciprocals. Results revealed that both additive and non-additive gene effects were important for inheritance of days to flowering, plant height and panicle exsertion with preponderance of additive gene effects. Inheritance of harvest index was controlled only by additive effects. While, inheritance of grain yield, panicle length and flag leaf area were governed by non-additive gene effects. ‘F’ value, showing an excess of dominant alleles in the parents, was significant only for grain yield. The average degree of dominance (H1/D) 0.5 was within the range of partial dominance for days to flowering, plant height, panicle exsertion and harvest index. At least two major groups of genes controlled the inheritance of plant height, and panicle length and flag leaf area, four major groups the inheritance of harvest index and one group the inheritance the other traits. The highest value of relative heterosis was observed for panicle exsertion and grain yield. Wr-Vr graphic analysis indicated that increase of flag leaf area, plant height, panicle exsertion and panicle length was under the control of dominance alleles, but harvest index was increased by recessive alleles. Due to the importance of non-additive components for grain yield, panicle length and flag leaf area, biparental mating and/or reciprocal recurrent selection could be used for genetic improvement of these characters. Predominance of additive effects for remainder of the traits demonstrated that breeding methods based on selection may be advantageous in improving of these traits in rice using the studied materials.

The experimental material includes four lines, ten testers of castor, their forty hybrids developed by line × tester design and standard check (GCH- 9) were evaluated by the use of RBD with three replications. Mean sum of squares of both general and specific combining ability were significant for all traits when analysis of variance for combining ability tested, which signified presence of additive gene action and non-additive gene action were pivotal in the inheritance of these traits. The variance ratio lesser than unity of both general and specific combining ability were exhibited that the non-additive gene action was primary for the expression of most of the traits studied but variance ratio greater than unity of both general and specific combining ability were exhibited that the additive gene action for length of primary raceme(cm), plant height up to primary raceme and effective length of primary raceme (cm), Parents; IPC 30, JI 518, JI 531 and 532, were found good general combiner for seed yield per plant that is revealed by gca effects. The estimates of sca effects of crosses signified that crosses IPC 30 × JI 533, IPC 31 × JI 532 and SKP 126 × JI 532 displayed maximum significant and sca effects are positive for seed yield per plant.

The current study was conducted at the agriculture research farm of the Department of Genetics and Plant Breeding, School of Agriculture, Lovely Professional University, Punjab during the kharif season 2022. A Randomized Block Design (RBD) with three replications were used to study correlation and path including 27 rice germplasm for the thirteen traits studied viz. Days to 50% flowering, Plant height (cm), Panicle length (cm), Number of tillers per plant, Number of spikelets per panicle, Flag leaf length (cm), Flag leaf width (cm), Number of filled grains per panicle, Days to maturity, Single plant yield (g), Test weight (g), Biological yield (g) and Harvest Index. Finding reveled that genotypic correlation coefficients were higher than phenotypic correlation coefficients for most of the characters studied indicating slight environmental effects over the traits. Single plant yield had significant positive correlation with harvest index (0.873, 0.976), Test weight (0.686, 0.738), panicle length (0.497, 0.603), number of tillers per plant (0.459, 0.505), days to maturity (0.398, 0.677), number of filled grains per panicle (0.395, 0.461) and days to 50 %flowering (0.253, 0.607) at phenotypic and genotypic level that were found to be helpful in encouraging rapid improvement of yield. Path coefficient analysis indicates that the harvest index (0.735, 0.999) had the highest direct and positive effect on single plant yield followed by biological yield (0.135, 0.459), days to maturity (0.088, 0.317), flag leaf width (0.087, 0.155) at both phenotypic and genotypic level respectively. These results revealed that single plant yield had maximum positive indirect effect through harvest index, biological yield, plant height, number of total tillers and number of filled grains per panicle. Hence, selection for these characters could bring improvement in yield and yield components.

Preharvest infection by Aspergillus flavus Link ex Fries and subsequent aflatoxin contamination of maize (Zea mays L.) grain are major production problems. Ear moisture loss rate (EMLR) is an important component of hybrid performance and maturity, and to some extent determines the suitability of a hybrid for a geographical area. A 10-parent diallel experiment was conducted in 1992 and 1994 to study the genetic nature of both percent kernel infection (PKI) by A. flavus and EMLR. General combining ability (GCA, V$\sb{\rm g}$), specific combining ability (SCA, V$\rm\sb{s}$), and reciprocal mean squares for PKI were significant. The ratio $\rm 2V\sb{g}/(2V\sb{g}+V\sb{s}$) was 0.54, indicating that both GCA and SCA were important. The GCA, SCA, and reciprocal effects for PKI varied across years, which implied that more reliable information could be obtained by conducting multi-year experiments. The EMLR was measured with an electronic probe device. First probe moisture (30DPM) and second probe moisture (51DPM) were recorded in the field at 30 and 51 days after midsilk, respectively. The GCA and reciprocal mean squares were significant, whereas SCA was not significant for EMLR. The 2V$\rm\sb{g}/(2v\sb{g}+V\sb{s}$) ratio was 0.81, indicating that GCA effects were more important than SCA effects for EMLR. inbred lines L108, L605, and L654 showed significant, positive GCA effects for EMLR and Mo17 inbred line showed a negative GCA effect. 30DPM and 51DPM mean squares for F$\sb1$ hybrids were significant. A relatively low Probe1, high EMLR, and positive GCA and reciprocal effects for EMLR were important in lowering 51DPM. Any selection scheme for lowering 51DPM or harvest grain moisture should exploit the extranuclear genetic component(s) for EMLR and use parental lines with significant, positive GCA effects for EMLR, and relatively low 30DPM. No significant correlation exist between PKI and EMLR. However, a significant genotypic correlation was found between PKI and 51DPM, indicating that the breeding goal for lowering both 51DPM and PKI by A. flavus can be achieved simultaneously.

Combining ability of inbred lines is crucial information in maize hybrid breeding programs incorporating materials from various germplasm sources. This study was conducted to assess the gene action for grain yield and other agronomic traits for germplasm having varying resistance to Striga hermonthica and genetic. In a half diallel cross of ten parents, general and specific combining abilities for grain yield, plant and ear height, plant and ear aspect, ears and plants harvested, ear rot, husk cover, moisture and resistance to Striga hermonthica were determined. The grain yields of the single crosses were significantly higher for 1368STR x TZISTR1198, TZISTR1132 x CML442, TZISTR1174 x TZISTR1198 and TZISTR1199 x TZISTR1174. The importance of both GCA (50%) and SCA (50%) for grain yield, ear rot, ear texture and ears harvested were observed, but a preponderance of GCA was existed for AUSNPC, whereas plant and ear height, plant and ear aspect, and moisture content exhibited preponderant SCA. TZISTR1174, TZISTR1162, TZISTR1192, and CML442 were good general combiners for grain yield showing highly significant positive GCA effects of 0.40, 0.2, 0.17, and 0.22, respectively while lines TZISTR1199, TZISTR1192, TZISTR1174 and TZISTR1162 were good general combiners for resistance to Striga showing highly significant negative GCA effects of-646.99,-428.21,-338.00, and-76.51. These inbred lines could be exploited in hybrid breeding to develop high yielding Striga resistant maize varieties. Hybrids such as TZISTR1174 x CML312, TZISTR1192 x CML442and TZISTR1174 x 1368STR had significant positive SCA effects for grain yield whereas crosses like TZISTR1162×TZISTR1198, TZISTR1199×TZISTR1181, TZISTR1192×1368STR had highest negative significant SCA effects of-1453.19,-1058.28, and-808.252 for AUSNPC which can be used for direct production as single cross hybrids or developed further as three way cross hybrids.

Drought is one of the major environmental factors which threaten crop production worldwide. Combining ability parameters were estimated for six inbred lines of maize and their F1 crosses based on morph-physiological traits under three irrigation regimes (100 (con), 75 and 50% Field capacity (F.C)) at two locations (Ismailia and Rommana) and two growing seasons (2012 and 2013). The experiments were grown a split plot design in randomized complete block arrangement in three replications under field conditions. Results showed that, the majority of the measured traits were significantly affected by factors under study and their interactions. At 50% FC, flowering traits (anthesis, silking and ASI), no. of rows ear -1 (RE), proline content and peroxidase (POD) activity exhibited significant differences for both general (GCA) and specific (SCA) combining ability under Ismailia location, however, the GCA effects were comparatively higher than the SCA effects indicating the involvement of both additive and non-additive gene action in their inheritance. Kernels row -1 (KR) and grain yield plant -1 (YP) revealed significant differences for GCA, therefore only additive gene action was predominant in their inheritance under the same conditions. No. of rows ear -1 was

With an objective to identify potential parents and crosses for quantitative and nutrient related characters and to understand the gene action for different traits for further improvement, an investigation was carried out in barnyard millet with diallel analysis involving five parents (CO 2, ACM 145, ACM 161, ACM 331 and ACM 332). Five parents and twenty crosses were evaluated for thirteen quantitative and four nutrient traits. The GCA, SCA and RCA variances were significant for almost all the characters suggesting the importance of both additive and non-additive gene action with pre-ponderance of non-additive gene action and significant reciprocal differences indicating the inter action between cytoplasm and the nuclear gene effects. However, for single plant yield the gene action was additive as the ratio of GCA to SCA variances was more than one. In the evaluation of parents, taking per se performance and gca effects as criteria the parents in the order ACM 145, ACM 161 and CO 2 were identified as the best general combiners. The crosses ACM 145/CO 2 and ACM 145/ACM 161 were selected as superior over others based on per se performance, SCA effects and heterosis percent together and are suggested for utilization in heterosis breeding. Non-significant SCA effect was possessed by CO 2/ACM 145 and CO 2/ACM 161 and they could be used for improvement of grain yield by recombination breeding to isolate useful segregants.

Maize (Zea mays L.) growers need hybrids with fast ear moisture loss rate (EMLR) to reduce grain drying cost. A 10‐parent diallel experiment with reciprocals (Griffing's Method 3) was conducted for 2 yr to study the genetic nature of EMLR in maize. Field ear moisture was measured with an electronic probe device at 30 and 51 d after midsilk. Analysis of covariance (ANCOVA) was used to increase precision of treatment comparisons and parameter estimation since F1 crosses differed in midsilk dates and in growing degree days (GDD) between the first (Moisture1) and the second probe moisture readings (Moisture2). Adjusted plot means were used to compute combining abilities. General combining ability fixed variance component (GCA, Vg) and reciprocal component were significant, whereas specific combining ability fixed variance component (SCA, Vg) was not significant for EMLR. The 2Vg/(2Vg + Vg) ratio was 0.81, indicating that GCA effects were more important than SCA effects for EMLR. Significant, positive GCA effects for EMLR were detected in L108, L605, and L654 inbred lines and negative GCA effects in Mo17 inbred line. Non‐maternal component was significant for EMLR. Moisture1 and Moisture2 also were genetically controlled. A relatively low Moisture1, high EMLR, and positive GCA and reciprocal effects for EMLR were important in lowering Moisture2. Specific interaction between nuclear genetic component(s) and non‐nuclear genetic factors can be exploited for enhancing EMLR. Inbred lines L668, B73, and H111 had relatively low Moisture2 due to either relatively low Moisture1 or high EMLR or both. In general, Louisiana (L) lines had higher Moisture1, Moisture2, and EMLR than B73, H111, and Mo17.

Study of genetic diversity of rice is very important for rice breeders. In this study 64 genotypes for 14 agronomic traits were evaluated. Phenotypic variation coefficients of some of traits were high which showed essential variation in this traits. Principal component analysis detected 6 components which explained 74.66 percent of the total variations. The first component was related to generative traits such as number of spiklet per panicle, number of full grain per panicle, date of 50% flowering and length of panicle. In the third component, the date of complete maturity with -0.730 has negative effects on yield. Correlation analysis of morphological traits indicated a negative and significant relationship between early maturity and plant height, which showed early maturity cultivars had higher plant type. Results of stepwise regression analysis for early maturity, indicated that three traits such as date of 50% flowering, number of full grain per panicle and plant height showed higher variation and explained 54.3 percent of total early maturity variations. All traits were classified into 2 groups, by cluster analysis and traits belonged to early maturity classified as a sub-group. Genotypes were classified into 4 groups by using method of Ward,s minimum variance and squared Euclidean distance. Native cultivars from the view point of early maturity and yield components had useful information for rice breeding. Key words: Genetic diversity, rice, morphological traits.

An experiment was conducted with a view to obtain information of genetic parameters of variation and character association for 13 quantitative traits in a set of 64 rice cultivars of Assam. The study revealed significant differences for all the traits under study. Highest genotypic coefficient of variation was observed for the trait biological yield followed by harvest index and grain yield. More than 80% heritability was observed for all the traits except grain yield, effective tillers per plant and biological yield. Genetic advance as per cent of mean was highest for biological yield followed by harvest index, filled grains per panicle and grain yield. Higher magnitude of genetic advance along with considerably high heritability observed for harvest index, filled grains per panicle and biological yield indicated that these traits could be considered for selection to obtain high genetic gain. Character association studies indicated that direct selection of 100 - grain weight, grain length, grain breadth, biological yield and harvest index, would bring about improvement in grain yield. Non-significant association of grain yield with important yield attributes viz., filled grain per panicle, tillers per plant and panicle length were due to their strong association with duration of genotypes, which in turn was negatively associated with grain yield. Recombination breeding and recurrent selection, therefore, could be suggested to break the negative linkage in order to achieve further genetic improvement.

For a better understanding of the inheritance of seed yield traits in Quinoa (Chenopodium quinoa) Willd., a half-diallelic crossing experiment with six diverse but uniform breeding lines was conducted. True hybrid plants were detected by means of differences in panicle colour in 14 out of the 15 crosses performed. The agronomic performance of 14 F2 populations and six parental lines was evaluated in field trials on fertile clay soil. General and specific combining ability of the lines (GCA and SCA) were estimated. Highly significant differences in GCA effects were found between the lines for plant height at maturity, early flowering, early maturity, seed yield and thousand seed weight. Significant SCA effects were only found for plant height at maturity. However, SCA effects were rather small and accounted for 7% of the total variance. The finding of large GCA effects and low SCA effects suggests that best selection results could be expected from crosses between the agronomic best performing genotypes.

This study aimed to estimate the genetic variability of 36 upland rice genotypes for yield and its components, and determine trait association among morphological traits. The field experiment was conducted using simple lattice design at two locations (Guraferda and Gojeb) during 2016 main cropping season. Analysis of variance for individual locations revealed significant differences (P≤0.05) among genotypes for most of the studied traits at Guraferda, however number of fertile tillers per plant, number of unfilled grains per panicle, non-fertile tillers per plant, panicle length, thousand grain weight and biological yield were found being non-significant. Similarly, the genotypes showed significant difference (P≤0.05) for plant height, number of filled grain per panicle, days to maturity, number of primary branches per panicle and grain yield however the remaining traits were showed non-significant difference among genotypes at Gojeb. Combined analysis of variance over the two locations revealed significant differences (P≤0.05) among the genotypes for most of the studied traits, while genotype x location interactions showed significant differences for the traits, total number of tillers per plant, plant height, days to 50% heading, days to maturity and grain yield. The mean over the two locations showed, wide ranges for number of filled grains per panicle (24-123), days to 50% heading (50-83) and grain yield (15-34 q/ha). The genotypic coefficient of variation ranged from 2.3% for plant height to 19.5% for number of filled grains per panicle, and phenotypic coefficient of variation (PCV) ranged from 4.0% for panicle length to 20.2% for filled grains per panicle. High broad sense heritability (H 2 B) estimates were obtained for number of filled grains per panicle (93.3%) and days to 50% heading (61.6%); while low H 2 B value was found for plant height (20.1%), number of primary branches per panicle (15.1%) and grain yield (14.4%). The estimates of genetic advance as the percentage of the mean (GAM) ranged from 2.1% for plant height to 38.8% for number of filled grains per panicle. High H 2 B coupled with high GAM were obtained for number of filled grains per panicle, which indicates that this trait can be effectively improved through selection. Grain yield showed significant and positive genotypic correlation with 1000-grain weight, days to 50% heading, days to maturity and harvest index. Similarly, it showed significant and positive phenotypic correlation with panicle length, number of filled grains per panicle, 1000-grain weight, fertile tillers per plant and number of primary branches per panicle. Path coefficient analysis at genotypic level revealed high and positive direct effect of days to heading (0.7), 1000-grain weight (0.6), days to maturity (0.3) and harvest index (0.2). The detected positive correlation indicated that, increases in the value of one trait results in increasing the correlated traits. Keywords: Broad sense heritability, Upland rice, Variability, DOI : 10.7176/JBAH/9-3-02

In the present investigation, the four cross combinations of Punjab Padmini X Panruti local, Dharmapuri local X Panruti local, Punjab Padmini X Parbanikranthi and Dharmapuri local X Parbanikranthi and three bhendi populations, BIP, F2, and F3, were developed in 2019, and these populations were evaluated in 2020 to determine the extent of genetic variability, heritability, and genetic advance for twelve bhendicharacters. Significant variances in BIP compared to the population of F2 and F3 in most characters have been noted that showed high mean and wider variations in PCV and GCV in fruit length, number of fruits per plant and plant yield. High heritability of BIPS was revealed by Punjab Padmini x Parbanikranthi for the traits viz., days to 50 per cent flowering, number of fruits per plant, fruit length, fruit girth and fruit yield per plant which revealed the importance of additive gene action for these traits. This is indicative of both additive and non-additive gene action (dominance and epistasis). Hence, selection could not be practiced in the immediate segregating generations. These two characters also showed unfavourable association with fruit yield per plant in BIPs which indicated that all the unfavourable linkages were not broken down through intermating in the early segregating generation. Thus, selection should be postponed to later generations after intermating in one or two subsequent to obtain potential recombinants.