Rice Populations Research Articles

Principal component and cluster analysis in grain appearance, milling and cooking quality traits in rice (Oryza sativa L.)

Rice grain quality characteristics such as grain appearance, milling, cooking, and eating parameters are quite complex phenotypic attributes. The rice grain quality is governed principally by the genetic makeup of the rice variety, the biochemical composition of rice grain, and the bio-physical environment where it is produced or grown. In addition to this grain quality is also affected by the moisture conditions of rice gains at the time of processing, the equipment by which rice is processed to a finished product, and to some extent how the product is stored. It is necessary to improve grain quality traits in rice to meet the consumers' demand for premium quality rice, reduce loss at the time of milling, increase production efficiency by increasing total head rice yield, and give more profit to producers and traders of the rice supply chain. This investigation aimed to evaluate the extent of diversity present in the population comprising one hundred-five genotypes for fifteen-grain quality attributes through principal component analysis and cluster analysis. The principal component analysis identified five principal components, (PCs) accounting for 73.10% of the sum total of variations perceived between the rice genotypes of the population. From the biplot analysis of PC1 and PC2, as the two axes of a 2-dimensional coordinate plain, it was found that the grain quality traits, kernel L/B ratio, water uptake, gel consistency, head rice recovery, kernel length after cooking, thousand-grain weight, milling percentage, and kernel length have a greater contribution to the total diversity of the rice population. By using UPGMA cluster analysis, all 105 genotypes of the population were classified into five discrete groups or clusters. The observed inter-cluster distance was largest between the clusters of cluster I and cluster III (149.22), the next largest inter-cluster distance was between cluster II and cluster IV (128.35), and that of cluster III and cluster IV was (109.61) which indicated significant genetic divergence among the genotypes. A larger inter-cluster distance between the clusters suggests the possibility of harnessing heterosis for the quality traits under study as they possess higher mean values for quality attributes with corresponding greater diversity.

Effectiveness of pre-emergence herbicides on weed population and yield of boro rice (cv. BRRI dhan58) under different dose

Weed management is crucial for optimal crop performance in rice cultivation. In this respect, an experiment was conducted at the Agronomy Field Laboratory (AFL), Bangladesh Agricultural University (BAU), Mymensingh, from December 2019 to May 2020 and aimed to evaluate the effectiveness of various herbicide treatments on weed management and crop performance in rice cultivation, focusing on the variety BRRI dhan58. The study included a control group and various herbicide treatments: half the recommended dose (RD), RD, and a double dose of pendimethalin, bensulfuron methyl + acetachlor, bensulfuron methyl + bispyribac sodium, pretilachlor, and butachlor. Eleven weed species from six families infested the plots. The results showed that double doses of pre-emergence herbicides resulted in lower weed populations (WP) (m-²), reduced weed dry weight (DW) (gm-2), and higher weed control efficiency (WCE %). The highest weed control efficiencies at 30 DAT were 94.58% for Bensulfuron methyl + Acetachlor and 94.38% for Pretilachlor. The double dose of Bensulfuron methyl + Acetachlor achieved the lowest WP and DW and the highest WCE. Crop performance improved significantly with the double dose of Bensulfuron methyl + Acetachlor, resulting in the highest PH, a more significant number of effective tillers (NET) hill-1, 1000-grain weight (TGW), grain yield (GY), straw yield (SY), biological yield (SY), and harvest index (HI). The second-highest GY was observed with the double dose of Bensulfuron methyl + Bispyribac sodium. The study concluded that the double dose of Bensulfuron methyl + Acetachlor was the most effective weed management strategy, leading to the highest grain yield in boro rice. These findings highlight that using a double dose of Bensulfuron methyl + Acetachlor not only offers superior weed control but also maximizes grain yield, making it the most effective weed management strategy for boro rice cultivation and a practical recommendation for farmers seeking to optimize productivity through targeted herbicide application.

Intraspecific variability of rice root knot nematodes across diverse agroecosystems for sustainable management

In the rice agroecosystems of Southeast Asia, rice root knot nematode (Meloidogyne graminicola) significantly impairs yield, representing a major species within the ‘graminis-group’ known for its morphological similarities with other root knot nematodes (RKNs). This study delves into the variations in reproductive potential, morphology, morphometrics, and genetic diversity among thirty RKN populations in rice across three distinct agroecological zones in Jharkhand, India. Despite notable differences in reproductive potential among the populations, morphological and morphometric correlations to reproductive potential were inconclusive. However, male and juvenile morphometrics were crucial for identifying intraspecific variability. Genetic analysis utilizing five molecular markers (ITS, 18 S rRNA, D2-D3 of 28 S, COX-I, and COX-II) affirmed the populations as M. graminicola, with ITS marker revealing significant intraspecific variability. Phylogenetic analysis underscored the close relationship between M. oryzae and M. graminicola, distinct from other mitotic RKN species. Low genetic distance and nucleotide diversity, coupled with high haplotype diversity, negative Tajima’s D, and Fu’s Fs of haplotype network analysis, suggested that all M. graminicola populations are expanding. These findings highlight the urgent need for comprehensive management strategies against M. graminicola, providing valuable insights for growers, extension officials, and plant breeders to develop targeted management approaches and resistance breeding programs.

Candidate genes for alkali tolerance identified by genome-wide association study at the seedling stage in rice (Oryza sativa L.)

Alkali stress is one of the most serious abiotic stresses limiting crop yield and it has become an increasingly serious global problem in recent years. Alkalinity tolerance (AT) at the seedling stage is one of the determinant factors for establishment of rice population under alkaline stress condition. Here, we evaluated and measured seven traits related to AT of 528 diverse rice accessions at the seedling stage. Xian accessions were generally more alkali-tolerant than Geng accessions. GJ-tmp accessions showed the most alkali tolerance in the Geng subgroups and XI-1B accessions had the weakest alkali tolerance in the Xian subgroups. A total of 121 QTLs were identified for AT by genome-wide association study (GWAS), and five important candidate genes, LOC_Os01g19800, LOC_Os01g20160, LOC_Os01g52500, LOC_Os01g67370 and LOC_Os03g03900, were selected by gene function annotation, haplotype analysis, and qRT-PCR. Pyramiding of multiple AT advanced candidate genes is a favorable strategy for improving AT of rice varieties. Our study has screened alkali-tolerant germplasm resources and provided valuable genetic information for alkali-tolerant rice breeding.

Recent Crop-To-Weed Adaptive Introgression Has Reshaped the Genomic Composition and Geographical Structure of US Weedy Rice (Oryza spp.).

Weedy rice is a close relative of cultivated rice (Oryza sativa) that infests rice fields worldwide and drastically reduces yields. To combat this agricultural pest, rice farmers in the southern US began to grow herbicide-resistant (HR) rice cultivars in the early 2000s, which permitted the application of herbicides that selectively targeted weedy rice without harming the crop. The widespread adoption of HR rice coincided with increased reliance on hybrid rice cultivars in place of traditional inbred varieties. Although both cultivated and weedy rice are predominantly self-fertilising, the combined introductions of HR and hybrid rice dramatically altered the opportunities and selective pressure for crop-weed hybridization and adaptive introgression. In this study, we generated genotyping-by-sequencing data for 178 weedy rice samples collected from across the rice growing region of the southern US; these were analysed together with previously published rice and weedy rice genome sequences to determine the recent genomic and population genetic consequences of adaptive introgression and selection for herbicide resistance in US weedy rice populations. We find a reshaped geographical structure of southern US weedy rice as well as purging of crop-derived alleles in some weed strains of crop-weed hybrid origin. Furthermore, we uncover evidence that related weedy rice strains have made use of different genetic mechanisms to respond to selection. Lastly, we identify widespread presence of HR alleles in both hybrid-derived and nonadmixed samples, which further supports an overall picture of weedy rice evolution and adaptation through diverse genetic mechanisms.

Genome-Wide Dissection of Selection on microRNA Target Genes Involved in Rice Flower Development.

Although genome-wide studies have identified a number of candidate regions evolving under selection in domesticated animals and cultivated plants, few attempts have been made, from the point of a definite biological process, to assess sequence variation and characterize the regimes of the selection on miRNA-associated motifs. Here, we performed a genome-wide dissection of nucleotide variation and selection of miRNA targets associated with rice flower development. By sampling and resequencing 26 miRNA targets for globally diverse representative populations of Asian cultivated rice and wild relatives, we found that purifying selection has reduced genetic variation at the conserved miRNA binding sites on the whole, and highly conserved miRNA binding sequences were maintained in the studied rice populations. Conversely, non-neutral evolution of positive and/or artificial selection accelerates the elevated variations at nonconserved binding sites in a population-specific behavior which may have contributed to flower development-related phenotypic variation. Taken together, our results elucidate that miRNA targets involved in flower development are under distinctive selection regimes during rice evolution.

Quantitative trait locus mapping and OsFLOq12 identification for rice grain hardness: towards improved rice flour for wheat substitution.

Recent shifts in consumer dietary preferences have led to a significant decline in rice consumption in Korea, resulting in surplus rice production. To address this issue, rice flour has been proposed as a substitute for wheat flour. However, the physical, chemical and structural differences between rice and wheat, particularly in grain hardness, pose challenges in using rice flour as an alternative. Understanding the genetic factors that influence rice grain hardness is crucial for improving the milling process and producing high-quality rice flour suitable for wheat flour substitution. In this study, various grain traits, including length, width, thickness, length-to-width ratio and hardness, were measured in a population of brown and milled rice. Quantitative trait locus (QTL) analysis revealed a significant association between grain hardness and thickness, with QTLs for grain hardness mapped on chromosomes 1 and 12 for brown and milled rice, respectively. A total of 20 candidate genes related to grain hardness were identified through QTL analysis. Among them, OsFLOq12 (LOC_Os12g43550) was identified as a key gene influencing grain hardness, which encodes a Ras small GTPase. Phenotypic analysis showed differences in endosperm appearance and particle size between lines with low and high grain hardness. The genetic analysis of OsFLOq12 revealed a single nucleotide polymorphism associated with grain hardness. This study provides valuable insights into the genetic background of grain hardness, offering a foundation for breeding rice varieties optimized for flour production as a viable substitute for wheat flour. © 2024 Society of Chemical Industry.

Nested association mapping population in japonica rice: Development, characterization, and application in genome-wide association studies

Multiparental mapping populations hold great potential for dissecting quantitative traits and rapidly identifying genetic determinants. We developed a japonica nested association mapping population, KNU_NAM, comprising 880 lines derived from ten recombinant inbred lines (RILs) families of prominent varieties and the elite Korean variety Shindongjin. Genetic characterization of KNU_NAM revealed 48,159 polymorphic SNPs, with family counts ranging from 18,787 to 42,578 and an average of 30,019 SNPs per family. Further molecular diversity analysis of KNU_NAM indicated reduced population structure and broad genetic diversity. Genome-wide association studies (GWAS) on five morphological traits identified 47 significant marker-trait associations (MTAs), with a set of 18 MTAs located on chromosome 9. Linkage disequilibrium (LD) block analysis of this region revealed 15 haplotypes and identified five key genes associated with panicle architecture: OsDEP1, OsEATB, OsLGD1, and OsSPL18. Additionally, two non-synonymous MTAs on chromosome 7 were located on the exon of OsPRR37/Ghd7.1, a gene associated with plant height, heading date, and grain number per panicle. Further phenotypic performance analysis of haplotypes from these hotspot regions revealed significant differences in the targeted traits. The study validates the potential of KNU_NAM and GWAS for high-resolution genetic mapping in rice breeding programs, highlighting the utility of these populations for enhancing genetic diversity and improving trait selection in rice.

Trait Association Studies to Determine Selection Indices in F5 Segregating Populations of Rice (Oryza sativa L.)

The experiment consisted of 38 promising F5 breeding lines developed and evaluated for correlation coefficient, path coefficient and selection indices studies with four check varieties viz., NVSR-2435, Sardar, Lalkada Gold and GR-18 in RBD with three replications during kharif-2023 at RRRS, Vyara, Gujarat. Genotypic correlation analysis revealed that grain yield per plant appeared to be positively and significantly correlated with productive tillers per plant, plant height, panicle length, straw yield per plant and 100 grain weight, which suggested that these characters can be improved simultaneously towards higher grain yield per plant by direct selection. Genotypic path analysis revealed that positive and direct effects on grain yield per plant were exhibited by days to maturity, productive tillers per plant, panicle length, 100 grain weight and straw yield per plant. Among these traits, panicle length, productive tillers per plant, 100 grain weight and straw yield per plant exhibited direct effect along with highly significant and positive association with grain yield per plant. Therefore, selection for such traits may be considered as most important yield attributing characters. The negligible residual effect of 0.037 was observed in path analysis, indicates that the model explained large proportion of variance. Thirty-one selection indices were constructed in all possible combinations of grain yield per plant (X1) along with four components viz., productive tiller per plant (X2), panicle length (X3), 100 grain weight (X4) and straw yield per plant (X5) through equal weight method. Among all the selection indices, the relative efficiency (%) and expected genetic advance (GA) was noted maximum with four characters selection index (I1245) compared to grain yield per plant (I1).

Grain Appearance Quality of Parental and \(F_2\) Segregating Populations of Aus Rice (Oryza sativa L.)

Longer grain length with smaller grain breadth, length-breadth ratio and 1000-grain weight is considered desirable character for the development of fine grain premium quality rice. In the present experiment, grain appearance quality of 15 F2 families and 10 parental genotypes were determined to select fine grain rice. The maximum mean value for thousand seed weight was found from the genotypes P2 (29.32g), P1 (28.89g), and F2 generations of P2 x P5 (32.77g), P2 x P1 (27.30g), P1 x P4 (26.04g) and were considered as high yielders in terms of grain weight. The highest mean values for grain length were found from the genotypes P6 (9.95 mm; grain breadth 2.23 mm), P7 (9.36 mm; grain breadth 2.62 mm), and F2 generations of P6 x P7 (9.46 mm; grain breadth 2.44 mm), P3 x P6 (9.40 mm; grain breadth 2.18 mm), P7 x P6 (9.37 mm; grain breadth 2.29 mm), P7 x P3 (9.36 mm; grain breadth 2.33 mm). The F2 progenies of the cross P1 x P4 (7.79 to 11.61 mm) and P6 x P3 (7.69 to 11.11 mm) showed extremes performance for grain length indicating transgressive segregation for this trait. The superior genotypes with desirable grain characters could be selected from transgressive segregation of F2 families for the development of new varieties of fine grain rice.

Evaluating the effect of organic NPK granules on yield, nutrient uptake, post-harvest soil fertility and soil microbial population in rice (Oryza sativa L.)

Rice is the most important and staple food crop for more than two third of population of India. India is the second largest rice producing country in the world after China. Although, rice planted area in India is 40 per cent higher than in China, Indian rice production is 30 percent below Chinese production because of lower yields. Among several constraints of production, nutrient management plays a key role in realizing sustainable yield from any given cultivation practices. Integrated nutrient management system plays a vital role in balancing the soil fertility and plant nutrient supply to an optimum level through the judicious and efficient use of chemical fertilizers, green manure, FYM and biofertilizers leading to an eco-friendly approach and economically viable solution for this problem. Continuous integrated use of organic manures with chemical fertilizers would be quite promising in assessing the sustainability of a cropping system vis-à-vis monitoring the soil properties. To investigate further, a field experiment was conducted at the Experimental Farm, Department of Agronomy, Annamalai University, Annamalai Nagar, Cuddalore district of Tamil Nadu from June to September 2023 with a key objective of evaluating the effect of combined application of graded levels of conventional fertilizers along with organic NPK granules in lowland rice. The experiment was laid out in randomized block design with seven treatments comprised of different levels of conventional fertilizers along with organic NPK granules. Among the nutrient management evaluated, all the yield attributes of lowland rice viz., grain yield, straw yield, uptake of nutrients and post-harvest soil available nutrients were significantly influenced by the application of 70% NPK through synthetic fertilizers and 30% NPK through organic granules. Combining conventional fertilizers along with organic NPK granules improved nitrogen use efficiency via metabolite production, enzyme activity stimulation, and microbial rhizosphere interactions significantly enhancing the yield attributes and yield.

Volatile Organic Compounds Produced by Bacillus sp. Strain R2 Inhibit Aspergillus flavus Growth In Vitro and in Unhulled Rice.

Volatile organic compounds (VOCs) produced by Bacillus species exhibit biocontrol activity against fungal pathogens of fruits and vegetables. However, research on the effect of VOCs on Aspergillus flavus in stored grains is limited. This study aimed to investigate the effects of VOCs extracted from the strain R2, which was isolated from unhulled rice and identified as Bacillus paramycoides on A. flavus in vitro and unhulled rice. R2 VOCs effectively inhibited conidial germination and the hyphal growth of A. flavus in vitro. Moreover, R2 VOCs reduced the fungal population, aflatoxin B1 (AFB1) levels, and free fatty acid (FFA) value by 90.8%, 67%, and 38.7%, respectively, in unhulled rice. Eighteen R2 VOCs were identified using headspace solid-phase micro-extraction gas chromatography-mass spectrometry, and the individual activity of the VOCs against A. flavus was tested in vitro. Benzaldehyde (Ben) and 3,7-dimethyl-1-octanol (Dmo) showed strong inhibitory activities against A. flavus on PDA plates, with inhibition rates of 100% and 91.2%, respectively, at a concentration of 20 μL/dish. Ben at the concentration of 0.09 mg/mL, Dmo at the concentration of 0.07 mg/mL, or a mixture of both at halved concentrations could reduce the fungal population, AFB1 levels, and FFA content in unhulled rice. Our findings suggest that R2 VOCs are good alternatives to traditional chemical fumigants for suppressing A. flavus in stored grains. However, further research is necessary to establish the optimal fumigation concentration of these two components in unhulled rice. The impact of their residues on grain quality should be explored through sensory evaluation and nutritional analysis, and their safety to the environment and human body should be evaluated through safety assessment.

Analysis of the Rice Raffinose Synthase (OsRS) Gene Family and Haplotype Diversity.

Based on the genome information of rice (Nipponbare), this study screened and identified six raffinose synthase (RS) genes and analyzed their physical and chemical properties, phylogenetic relationship, conserved domains, promoter cis-acting elements, and the function and genetic diversity of the gene-CDS-haplotype (gcHap). The results showed that these genes play key roles in abiotic stress response, such as OsRS5, whose expression in leaves changed significantly under high salt, drought, ABA, and MeJA treatments. In addition, the OsRS genes showed significant genetic variations in different rice populations. The main gcHaps of most OsRS loci had significant effects on key agronomic traits, and the frequency of these alleles varied significantly among different rice populations and subspecies. These findings provide direction for studying the RS gene family in other crops.

Substitutive Effects of Upland Rice and Soybean Plant Populations on the Performance of the Component Crops in Intercropping System

Substitutive Effects of Upland Rice and Soybean Plant Populations on the Performance of the Component Crops in Intercropping System

Multiomics of a rice population identifies genes and genomic regions that bestow low glycemic index and high protein content

To counter the rising incidence of diabetes and to meet the daily protein needs, we created low glycemic index (GI) rice varieties with protein content (PC) surpassing 14%. In the development of recombinant inbred lines using Samba Mahsuri and IR36 amylose extender (IR36ae) as parental lines, we identified quantitative trait loci and genes associated with low GI, high amylose content (AC), and high PC. By integrating genetic techniques with classification models, this comprehensive approach identified candidate genes on chromosome 2 (qGI2.1/qAC2.1 spanning the region from 18.62 Mb to 19.95 Mb), exerting influence on low GI and high amylose. Notably, the phenotypic variant with high value was associated with the recessive allele of the starch branching enzyme 2b (sbeIIb). The genome-edited sbeIIb line confirmed low GI phenotype in milled rice grains. Further, combinations of alleles created by the highly significant SNPs from the targeted associations and epistatically interacting genes showed ultralow GI phenotypes with high amylose and high protein. Metabolomics analysis of rice with varying AC, PC, and GI revealed that the superior lines of high AC and PC, and low GI were preferentially enriched in glycolytic and amino acid metabolisms, whereas the inferior lines of low AC and PC and high GI were enriched with fatty acid metabolism. The high amylose high protein recombinant inbred line (HAHP_101) was enriched in essential amino acids like lysine. Such lines may be highly relevant for food product development to address diabetes and malnutrition.

Analysis of Rice Demand in Klaten Regency

This study aims to analyze the influence of rice prices, population size, and income on rice demand, as well as to determine the elasticity of rice demand in Klaten Regency. A descriptive analysis method was employed using secondary time series data over a period of 10 years (2013-2022), which included rice demand and population data. The data analysis model applied was multiple linear regression and classical assumption tests. Hypotheses were tested using t-tests, F-tests, and R-squared tests. The results indicate that: 1) Rice prices have a negative influence on rice demand, with a p-value of 0.06; 2) Population size has a positive influence on rice demand, with a p-value of 0.003; 3) Per capita income positively influences rice demand, with a p-value of 0.004; and 4) Rice demand is inelastic, as the price elasticity coefficient (0 < Ep < 1) suggests that changes in rice demand are smaller than changes in rice prices. Income elasticity (EI > 1) indicates that rice demand increases significantly with higher income levels.

Landrace introgression contributed to the recent feralization of weedy rice in East China

This study leveraged knowledge of the specific known cultivar progenitor "Nanjing11" of a weedy rice population from East China, and discovered that the landrace introgression greatly contributed to the recent feralization of modern cultivars, including the introduction of the Rc gene that confers key weedy traits such as red pericarp and seed dormancy.

Analysis of Rice Blast Fungus Genetic Diversity and Identification of a Novel Blast Resistance OsDRq12 Gene.

The rice blast fungus Magnaporthe oryzae poses a significant challenge to maintaining rice production. Developing rice varieties with resistance to this disease is crucial for its effective control. To understand the genetic variability of blast isolates collected between 2015 and 2017, the 27 monogenic rice lines that carry specific resistance genes were used to evaluate blast disease reactions. Based on criteria such as viability, virulence, and reactions to resistance genes, 20 blast isolates were selected as representative strains. To identify novel resistance genes, a quantitative trait locus analysis was carried out utilizing a mixture of the 20 representative rice blast isolates and a rice population derived from crossing the blast-resistant cultivar 'Cheongcheong' with the blast-susceptible cultivar 'Nagdong'. This analysis revealed a significant locus, RM1227-RM1261 on chromosome 12, that is associated with rice blast resistance. Within this locus, 12 disease resistance-associated protein genes were identified. Among them, OsDRq12, a member of the nucleotide-binding, leucine-rich repeat disease resistance family, was chosen as the target gene for additional computational investigation. The findings of this study have significant implications for enhancing rice production and ensuring food security by controlling rice blast and developing resistant rice cultivars.

Impact of IPM practices on microbial population and disease development in transplanted and direct-seeded rice.

Integrated pest management (IPM) is a comprehensive approach to managing diseases, focusing on combining various strategies to reduce pathogen populations effectively and in an environmentally conscious way. We investigated the effects of IPM on beneficial microbial populations and its relationship with pathogen populations in both direct-seeded rice (DSR) and transplanted rice (TR) systems. This study demonstrates that IPM practices have significantly higher populations of beneficial microbes, such as Trichoderma harzianum and Pseudomonas fluorescens, and lower level of the pathogen Fusarium verticillioides compared to non-IPM (farmer practices). The average mean population of T. harzianum was 6.38 × 103 CFU/g in IPM compared to 3.22 × 103 CFU/g in non-IPM during 2019 in TR at Bambawad. P. fluorescens mean population in 2019 was significantly higher in IPM (4.67 × 103 CFU/g) than in non-IPM (3.82 × 103 CFU/g) at the Karnal location in DSR. The F. verticillioides populations were significantly lower in IPM fields (9.46 × 103 CFU/g) compared to non-IPM fields (11.48 × 103 CFU/g) during 2017 at Haridwar in TR. Over three years, a significant increase in the populations of beneficial microbes in IPM plots was observed in all three locations of both TR and DSR, highlighting the sustainable impact of IPM practices. Disease dynamics analysis revealed that IPM effectively managed key diseases in both DSR and TR systems, with significant correlations between microbial density and disease severity. A significant positive correlation was recorded between F. verticillioides population and bakanae incidence at all three locations. Sheath blight incidence was negatively correlated with P. fluorescens population in both TR and DSR. In DSR, bacterial blight and brown spot diseases are reduced with the increased population of T. harzianum. Bioagents T. harzianum and P. fluorescens reduced disease incidence, underscoring the role of beneficial microbes in disease suppression and their importance for sustainable production using IPM practices.

Inheritance pattern of Qualitative traits, Genetic analysis and association of yield attributes in F2 populations of Rice (Oryza sativa)

Understanding the extent of genetic variability within the segregating generations is crucial for identifying superior segregants with high yield and better market acceptability. Thus, the present study was carried out to quantify the extent of genetic variation available in the segregating population of rice. Three crosses, viz., CO 55 × IC 457996, CO 55 × IC 464685, and CO 55 × IC 115439 were evaluated using a non-randomized experimental design for six yield attributing and two physical grain quality traits in F2 generation. The inheritance pattern of basal leaf sheath colour and grain colour in CO 55 × IC 115439 indicate digenic complementary gene interaction (9:7), whereas grain colour in CO 55 × IC 464685 exhibits inhibitory gene action (13:3). The positively skewed nature of productive tillers per plant and single-plant yield in the F2 segregants emphasizes the need for intensive selection to facilitate rapid improvement due to the influence of complementary gene action. Moderate to high GCV with high heritability and GAM for traits such as plant height, productive tillers per plant, hundred seed weight, grain width, and single-plant yield in the F2 segregants underscore the prevalence of additive gene action and thus provide the most effective condition for simple phenotypic selection. Moreover, productive tillers per plant and single-plant yield showed a strong positive association in all the crosses. Therefore, productive tillers per plant can be considered an indicator trait when selecting high-yielding segregants for grain yield improvement.