Exploring the Morphological Diversity of Selected Abakaliki Local Rice Cultivars: A Study of Key Physical Traits and Variations

*Ogah Onwuchekwa

Biotechnology Department, Ebonyi State University, Abakaliki, Nigeria.

*Corresponding Author

DOI : https://doi.org/10.51584/IJRIAS.2024.906023

Received: 30 April 2024; Revised: 12 May 2024; Accepted: 17 May 2024; Published: 05 July 2024

ABSTRACT                                                                       

Abakaliki rice is unique compared to other rice grown in different parts of Nigeria, unfortunately, rice yield per hectare is low because smallholder farmers rely on local rice cultivars with low yield potentials, Therefore, identification of high-yielding locally adapted rice varieties in combination with high grain quality is the most effective strategy in increasing rice production in Ebonyi State. Hence, forty rice cultivars collected from different villages and local government areas in Ebonyi State were cultivated in a complete randomized block design in three replications to evaluate the morphological characteristics of the Abakaliki local rice cultivars using the standard rice evaluation method. The results showed that Nwangbashianya had the highest grain length with a mean value of 1.03mm followed by Akuje and Iron with the same mean value of   1.00 mm,. Mars had the maximum plant length with a mean value of 174.67cm, and maximum performance for 1000 grain per weight with a mean value of 4.13kg. The results also revealed varied number of primary panicles for which Iron recorded the highest mean value of   43.67. The maximum number of primary and secondary tillers were observed in Faro 15 and Offia with mean values of 6.33 and 4.00 respectively. Concurrent selection based on these best-performing cultivars with exceptional traits could lead to the development of high-yielding rice varieties in Ebonyi State.

INTRODUCTION

Rice production’s success hinges on various yield determination components, necessitating a holistic approach to parental selection beyond final yield alone (Kumbhar et al., 2013). Besides its caloric content, rice boasts high nutritional value, being rich in fiber, vitamins, and minerals while low in cholesterol and sodium, making it an essential energy source. Despite regional consumption disparities, global rice utilization has outpaced production in recent years (FAO, 2017). Therefore, efforts to bolster rice production are critical to meet market demands driven by population growth and future food security concerns.

Ebonyi State stands out as a major rice producer in Nigeria, witnessing remarkable production growth in recent years. The region’s conducive environment has led to the emergence of diverse rice varieties adapted to specific local conditions, often named after the towns where they are cultivated (Garris et al., 2005). However, achieving maximum yield remains a challenge due to factors like poor production practices, environmental stresses, and genetic variability. Studying the agronomic traits of Abakaliki rice germplasm is crucial for selecting appropriate breeding procedures, paving the way for the development of high-yielding varieties suited to local farmers’ needs. Different morphological traits contribute uniquely to rice production, serving as indispensable tools for selecting varieties based on agronomical, morphological, genetic, or physiological characteristics (Yuan, et al., 2021). Identifying promising morphological traits associated with quality and yield is vital for rice production in Ebonyi State and varietal development programs (Ashrafuzzaman et al., 2009). This study primarily focuses on evaluating the morphological characteristics of Abakaliki rice cultivars sourced from various local government areas of Ebonyi State to determine the yield-related traits to achieve optimum rice production in the area. Ultimately, such initiatives will bolster food security, enhance farmers’ livelihoods, and sustain the rice industry in Ebonyi State and beyond.

MATERIALS AND METHODS      

A total of forty rice cultivars were collected from different Local Government Areas of Ebonyi State (Abakaliki, Ikwo Ohaukwu, Ezza, and Izzi). The actual identity of the locally named cultivars and their sources of collection are shown below. The rice cultivars were all planted on the field under the same cultural practices.

Table 1: Identity of Locally Named Cultivars and Their Sources of Collection

Experimental Field Design and Layout

Seedlings were raised on different mapped-out nursery beds and covered with dried grasses to prevent birds from picking the grains till germination. After 30 days the rice was transplanted. The experimental field was cleared, ploughed, and harrowed manually, and demarcated in a complete randomized block design. A basal dose of N-P-K fertilizer (20:10:10) at the rate of 200 kg/ha was applied at 15 days after transplanting. Subsequently, urea was top-dressed at 100 kg/ha at 30 days after transplanting. Weeding was carried out manually at 21 days after transplanting. A second weeding session was conducted during panicle initiation, occurring approximately 42 days after transplanting.

 Data collection and measurement

Several yield-related agronomical characters were measured after 60days of transplanting which include tiller number (i.e. primary and secondary), plant height, length and width of flag leaf, days to maturity, panicle length, primary and secondary branching of panicles, spikelet vigor and fertility, spikelet exertion, 1000 grain weight, length and width of paddy, were evaluated based on standard evaluation system rice (Kundu et al., 2008).

Statistical analysis

The primary data collected from the above quantitative traits were analyzed by the analysis of variance (ANOVA) procedure using SPSS 20.0. Differences were declared statistically significant at P<0.05. Where significant differences were detected, the means were separated by the least Significant differences (LSD) at 5% probability level.

RESULTS

Morphological data revealed significant variations among rice cultivars. Primary tillers ranged from 2.33 to 9.33, with FARO 15 and 306 recording the highest mean values of 9.33 and 7.00, respectively, while Atom 3 and China exhibited the lowest mean values of 2.33 and 2.67. Secondary tillers ranged from 0.67 to 4.00, with Offia leading at 4.00, followed by 306 at 3.67, and CP and Nwadugo recording the lowest at 0.67. Plant height varied from 39.00cm to 174.67cm, with Mars being the highest at 174.67cm while Iron and Nwadugo were the lowest with 39.00cm and 63.33cm, respectively. Primary panicles ranged from 6.00 to 43.67, with Iron leading at 43.67 and Nwadugo being the lowest mean value of 6.00. Secondary panicles varied from 14.33 to 38.33, with R8 and Kpurukpuru topping at 38.33 and 37.00, respectively. Panicle length ranged from 14.03cm to 31.67cm, with Kpurukpuru) recording the longest at 31.67cm and Nwadugo at the shortest with 14.03cm. Spikelet vigor per plant ranged from 0.33 to 2.00, with Mars leading at 2.00 and several cultivars at the lowest with 0.33. Grain length varied from 0.57mm to 1.03mm, with Nwangbasianya  at 1.03mm and Kpurukpuru  at the lowest with 0.57mm. Grain width ranged from 1.97mm to 4.13mm, with Mars leading at 4.13mm and Nwadugo  at the lowest with 1.97mm. 1000-grain weight varied from 1.97g to 4.13g, with Mars at 4.13g and Nwadugo at the lowest with 1.97g. Spikelet fertility per plant ranged from 1.83 to 66.57, with Offia leading at 66.57 and Faro 55 at the lowest with 1.83. Flag leaf length ranged from 0.90cm to 1.70cm, with Kpurukpuru recording the longest at 1.70cm and Nwadugo at the shortest with 0.90cm.

Table 2: Mean Performance of 40 Rice Varieties in Primary and Secondary Tiller Count, Plant Height, Primary and Secondary Panicle Numbers, and Spikelet Vigor

NPT = Number of Primary Tillers, NST = Number of Secondary Tillers, PL = Plant Length, NPP = Number of Primary Panicle,NSP = Number of Secondary Panicle, PanL = Panicle Length t, SPKF= Spikelet Fertility, SKV = Spikelet Vigor,

Table 3 Mean performance of 40 Rice Cultivars in 1000 Grain Weight, Spikelet Fertility, Grain Length, Grain Width, and Panicle threshibility

PThresh =Panicle Threshability, 1000g/w = 1000 Grain Weight, SPKF= Spikelet Fertility, SKV = Spikelet Vigor, WGrain = Grain Width, LG = Grain Leng

DISCUSSION

To enhance potential rice yield, identifying key traits contributing to increased yield is crucial. Grain yield results from complex morphological and physiological processes, making selection based solely on yield ineffective, thereby shifting focus to yield-related traits (Efisue et al., 2008) Local farmers in Ebonyi State can utilize these traits for effective selection, aiding in crop yield improvement.    From the result of this analysis, Faro 15 and 306 displayed the highest number of primary tillers, while Offia had the most secondary tillers, indicating that there are high-yielding cultivars (Efisue et al., 2008)

Grain weight, determined by the weight of a thousand seeds, is a major determinant of rice yield, hence Mars and Atom 2 which exhibited the highest mean 1000-grain weight, may be a good cultivar in terms of yield. Flag leaf length which contributes to photosynthesis and grain filling, varied among cultivar with Kpurukpuru having the longest, and Nwadugo the shortest Additionally, panicle numbers significantly influenced grain yield, with Iron and 306 displaying higher primary panicle numbers, while R8 and Kpurukpuru had more secondary panicles. This variation in panicle numbers underscores their role in determining rice grain yield, influenced by factors like soil fertility and weather conditions (Mohammad et al 2002). Therefore, selecting superior genotypes based solely on overall yield is ineffective. Instead, selection should focus on individual components contributing to grain yield. Local farmers in Ebonyi State can utilize yield-related traits to identify stable and desirable characteristics, thus enhancing crop yield. The agronomical characteristics varied significantly among the 40 evaluated genotypes, suggesting that those traits may be influenced by genes, as well as environmental factors. This variation underscores the importance of considering individual traits in genotype selection for improving rice yield (Assuero, and Tognetti, 2010); Hussain et al.,2014).

In conclusion, all the l 40 evaluated genotypes displayed diverse agro-morphological traits relevant to rice production improvement and selection. Notably, Mars emerged as an exceptional genotype, boasting numerous yield-related attributes. Its remarkable traits include the longest plant length, highest 1000-grain weight, and notable spikelet vigor. Farmers and breeders in the studied area can capitalize on these advantageous characteristics for enhanced rice cultivation and rice improvement.

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