Elucidation of Genetic Parameters Controlling Yield and Quality Traits in Rice (Oryza sativa L.)

Background: Forty two crosses involving seven lines and six testers were studied for economically important yield contributing and quality traits to test the magnitude of genetic components and diversity. Formulation of efficient breeding methodology is possible by targeting the genetic architecture of genotypes. Methods: The systematic breeding programme involves generating genetic variability besides sorting off the diverse genotypes and utilizing the extreme phenotypes for producing stable varieties. Genetic diversity helps to achieve the greater continuum of genetic variability in segregating populations to reach for ideal selection of progenies. Heritability and genetic advance are other important selection parameters for retrieving better genotype through selection. Result: Significant differences in analysis of variance were recorded for all the traits. The results signified the greater value of phenotypic coefficient of variation (PCV) than genotypic coefficient of variation (GCV) and environment coefficient of variation (ECV) pertaining to the test traits studied. Among agronomical characters, the GCV and PCV were reported to be in higher estimate for number of productive tillers per plant, number of grains per panicle, single plant yield and among quality characters for gelatinization temperature (GT), length breadth (LB) ratio, gel consistency and amylose content. The present study adverted that among the yield and grain quality characters viz., number of productive tillers, number of grains per panicle, single plant yield, plant height, 1000 grain weight, milling percentage and grain length could be easily inherited to next generation due to high heritability. Whereas breadth elongation ratio and linear elongation ratio are influenced by environmental factors due to their low heritability. Further, the number of productive tillers, number of grains per panicle, single plant yield, plant height, Gel consistency and amylose content exhibited higher PCV, GCV, heritability and genetic advance and hence direct selection can be made for target traits.

Glycemic index studies in rice (Oryza sativa L.) varieties developed by ANGRAU

Twenty popular rice varieties developed by ANGRAU obtained from Regional Agricultural Research Station (RARS), Maruteru during Kharif – 2019, were screened for chemical quality traits viz., gel consistency, gelatinization temperature, amylose along with glycemic index.In our study, significant variation was observed among all the varieties for chemical traits but no significant variation was observed in case of glycemic index.The amylose content observed over the varieties ranged from 21.7 per cent to 24.73 per cent. All the varieties have intermediate amylose content. Gel consistency ranged from 37.67 (hard gel) to 75 (soft gel) with the mean of 52.57. The alkali spreading value was noticed to be low, intermediate and high among all rice varieties.Glycemic index rangedfrom 56.72 -66.43 with a general mean of 60.67. Furthermore, all the varieties were categorized as medium GI varieties (56-69). Among all the varieties, Pushyami has shown the least value (56.72) for glycemic index.From the present investigation, it is concluded that, Rice varieties such as Chandra, Indra, Sri Dhruthi, Swarna, Samba Mahsuri, Sujatha, Maruteru Samba, MaruteruMahsuri recorded intermediate amylose, alkali spreading value and medium GI, which are desirable for rice consumers while counting for better rice with the best quality and glycemic index.

Efficacy of Irrigation Interval after Anthesis on Grain Quality, Alkali Digestion, and Gel Consistency of Rice

The management of amylose and protein contents and cooking quality are the main challenges in rice macronutrients and quality improvement. This experiment was conducted to examine the rice grain quality, alkali digestion, and gel consistency responses to irrigation interval after anthesis. Three rice varieties (K1, K3, and K4) were subjected to different irrigation intervals (1, 2, and 3 d) after anthesis. The findings of this study showed that the protein content was markedly increased from 6.53–6.63% to 9.93–10.16%, whilst the amylose content was decreased significantly from 22.00–22.43% to 16.33–17.56% under stressed treatments at irrigation intervals, whilst the quantity of fatty acids was not affected. The 3-d irrigation interval recorded the highest protein content but the lowest amylose value. In addition, this treatment shows lower gelatinization temperature, but it is negatively associated with hard gel consistency under irrigation interval. This study highlights that the water management following a 3-d irrigation interval from anthesis is a useful and simple treatment to improve rice nutrients and grain cooking quality.

Influence of heat treatment on the nutrient composition and physicochemical characteristics of Adlai (Coix Lachryma-Jobi L.) and Obatanpa cross Lagkitan (OxL) corn variety (Zea Mays L. ‘Los Baños Lagkitan’)

The study aimed to investigate the effect of heat treatments on the proximate composition, caloric value, carbohydrate profile and physicochemical characteristics of Adlai and Obatanpa cross Lagkitan corn variety (OxL). Different percentages of Adlai were incorporated to OxL corn and sensory evaluation revealed that 90% adlai: 10% OxL corn blend was the most acceptable proportion. The raw, boiled and canned pure adlai, pure OxL corn and the most acceptable adlai-corn blend were used in the study. Results showed that after boiling, all samples fell under the soft gel consistency category (65-100 mm) and have a high gelatinization temperature (>74oC). In adlai, OxL corn and adlaicorn blend samples, values of moisture and crude fat increased significantly (p<0.05) from raw to heat-treated samples (boiling and canning), while those of crude protein, crude fiber, total ash and carbohydrate significantly decreased (p<0.05). The energy content (kcal/100 g) was highest in all raw samples while boiling and canning led in a significant (p<0.05) decrease. Moreover, there is a significant (p<0.05) reduction in starch and amylose content of all raw samples after boiling and further decreased by canning. However, the values of moisture, crude fat, total ash, carbohydrates, caloric value, starch and amylose for boiled and canned samples were not significantly (p>0.05) different. Overall, heat treatment significantly reduced the nutritional value of adlai, OxL corn and adlai-corn blend.

Evaluation of Grain and Nutritional Quality of Transplanted Aman Rice Under Different Nitrogen Levels

Quality is one of the key characteristics of rice and is largely governed by nitrogen application. An experiment was conducted to scrutinize the effect of nitrogen on quality characteristics of rice, with three nitrogen levels (viz. 50 kg N ha-1, 100 kg N ha-1 and 150 kg N ha-1) and four varieties/lines (viz. SAU ADL1, BRRI dhan70, BRRI hybrid dhan6 and SAU ADL11). Results revealed that quality characters of transplanted Aman rice were significantly influenced by nitrogen, variety and their interaction. Increasing trend was observed with the increasing level of nitrogen from 50 to 150 kg ha-1 regarding hulling percentage and milling outturn while decreasing trend was observed in case of apparent amylose content and imbibition ratio. Maximum protein content (9.60%) and gel consistency (96.16 mm) were recorded at 100 kg N ha-1. Among the studied materials, SAU ADL11 performed better in case of all studied parameters. Although interaction of 150 kg N ha-1 with SAU ADL1 and SAU ADL11 gave maximum value of hulling percentage and milling outturn. In interaction of 100 kg N ha-1 with these two lines gave maximum protein, gel consistency and satisfactory levels of all quality characters. So, it can be suggested to carry out further investigation with these two rice lines having 100 kg N ha-1. Bangladesh Agron. J. 2020, 23(1): 59-66

Cooking and functional properties of parboiled milled local rice marketed in the south-east zone of Nigeria

Imported rice is perceived to have better cooking properties than locally grown rice in Nigeria and it has increased its market share while reducing patronage for local rice. Rice in Nigeria has many applications, including consumption as whole cooked grain or dumpling or use as an adjunct in making beverages. Eighteen varieties of parboiled milled local rice and three imported rice varieties, coded Ip1, Ip2 and Ip3, were studied for their cooking and functional properties using standard methods. There was a significant (p<0.05) increase in the dimensions of all the rice varieties when cooked. There was a 25 g increase in the grain weight and an elongation ratio of more than 1.26 in all the rice varieties. Ghesua had the highest cooked grain weight (68.67 g) while Omor-Mas (6.00) and R-Bus (6.00) had the highest volume expansion ratio (VER). The VER was more than 3.00 for all the rice varieties. All the local rice varieties imbibed less water (17.67-25.33 ml) compared to the imported rice varieties (26.00-27.67ml) before they reached their optimum cooking time. The imported rice varieties were of soft gel consistency (89.67-73.50 mm) and intermediate amylose content (20.71-23.14 %) while the local rice varied in amylose and gel consistency. Abakiliki-Mas (27.00 mm) and R-8 (33.67 mm) were of hard gel-consistency, intermediate (21.11 %) and high amylose (27.21 %) content respectively and have not been exploited although they would be appropriate for making canned rice, dry mixes and rice-noodles.

Genetic dissection of eating and cooking qualities in different subpopulations of cultivated rice (Oryza sativa L.) through association mapping

Background Eating and cooking qualities (ECQs) of rice (Oryza sativa L.) determine consumer acceptance and the economic value of rice varieties. The starch physicochemical properties, i.e. amylose content, gel consistency, gelatinization temperature and pasting viscosity are important indices for evaluating rice ECQs. Genetic factors are required for development of rice varieties with excellent ECQs and association mapping is one of the promising approaches for discovering such associated genetic factors. Results A genome-wide association mapping was performed on a set of 253 non-glutinous rice accessions consisting of 83 indica and 170 japonica cultivated rice varieties through phenotyping for 11 ECQ traits in two consecutive years and genotyping with 210 polymorphic SSR and candidate-gene markers. These markers amplified 747 alleles with an average of 3.57 alleles per locus. The structure, phylogenetic relationship, and principal component analysis indicated a strong population differentiation between indica and japonica accessions and association mapping was thus undertaken within indica and japonica subpopulations. All traits showed a large phenotypic variation and highly significant phenotypic correlations were present between most of traits. A total of 33 and 30 loci were located for 11 ECQs in indica and japonica subpopulations respectively. Most of associated loci were overlapped with starch synthesis-related genes (SSRGs), and the Wx locus gathered 14 associated loci with the largest effects on amylose content, gel consistency and pasting viscosities. Eight subpopulation specific markers, RM588, Wx-(CT)n, SSI and SBE1 for indica subpopulation and RM550, Wxmp, SSIIa and SBE4 for japonica subpopulation, were identified, suggesting alleles of SSRGs showed the subspecific tendency. Nevertheless, allelic variation in SSIIa showed no tendency towards subspecies. One associated maker RM550 detected in japonica subpopulation for amylose content and pasting viscosity was verified a potential novel and stably expressed locus and could be selected for further fine mapping. Conclusion This study illustrated the potential for dissecting genetic factors of complex traits in domesticated rice subspecies and provided highly associated markers to facilitate marker-assisted selection for breeding high-quality indica or japonica rice varieties.

Influence of pineapple extract on physicochemical characteristics of cooked glutinous rice

Glutinous rice is an important crop in Southeast Asia. Pineapple had numerous potential to turn into added value. This research evaluated the impact of pineapple extract on physicochemical characteristics of cooked glutinous rice. The glutinous rice was soaked with pineapple extract in different percentage (0–2.5%) at ambient temperature for 12 hrs before cooking. The cooked glutinous rice was evaluated for gel consistency, water uptake ratio, volume increase ratio, cooking time and phytic acid content. Results showed that pineapple extract reduced gel consistency, cooking time, phytic acid while accelerating water uptake ratio, volume increase ratio. By incorporation of pineapple extract to glutinous rice during soaking, the physicochemical properties of cooked glutinous rice would be improved.

Estimation of Genetic Diversity in Rice (Oryza sativa L.) CMS Lines for High out Crossing Potential and Quality Traits

In the present study genetic diversity among 40 rice genotypes was evaluated using Mahalanobis D2 statistic based on morphological markers. Based on cluster analysis, the germplasms were grouped into 4 clusters of which Cluster I comprising of 23 genotypes was the largest group followed by the cluster II comprising of 15 genotypes, the clusters III and IV were represented by single genotype indicating high degree of heterogeneity among the genotypes. Maximum intra cluster distance observed in cluster II is (146.8) followed by cluster I (112.9) indicating the existence of variability among the genotypes within these clusters. The highest inter-cluster distance was observed between cluster IV and III (606.5), While the lowest was noticed between cluster II and III (222.9), describing that the genotypes included in these clusters were closely related. The kernel length, kernel length after cooking, kernel breadth, gel consistency, days to 50% flowering and plant height together contributed 90.1% towards total divergence. Therefore, these characters should be given importance during hybridization and selection of segregating populations. The genotypes falling in different clusters with the high mean for grain yield and other component characters can be utilized for the hybridization programme to obtain elite segregants.