Variation among Tanzania Rice Germplasm Collections Based on Agronomic Traits and Resistance to Rice Yellow Mottle Virus

William Titus Suvi,Mark Laing,Isack Mathew,Hussein Shimelis,Admire I T Shayanowako

doi:10.3390/agronomy11020391

William Titus Suvi, Mark Laing + Show 3 more

Open Access

https://doi.org/10.3390/agronomy11020391

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Abstract

Rice (Oryza species) is a commercial crop worldwide. Across Africa, the potential yield and quality of rice is diminished by a lack of high performance, locally adapted varieties, and the impact of rice yellow mottle virus (RYMV). The objective of this study was to assess the performance of a diverse collection of rice germplasm for RYMV resistance and agronomic traits, and to select promising lines for breeding for Tanzanian conditions. Fifty-four rice genotypes were field evaluated in two important rice production sites (Ifakara and Mkindo) in Tanzania, which are recognized as RYMV hotspots, using a 6 × 9 alpha lattice design with two replications. There was significant (p < 0.05) genotypic variation for agronomic traits and RYMV susceptibility in the tested germplasm. Seven genotypes with moderate to high RYMV resistance were identified, including Salama M-57, SSD1, IRAT 256, Salama M-55, Mwangaza, Lunyuki, and Salama M-19, which were identified as new sources of resistance genes. Positive and significant correlations were detected between grain yield and number of panicles per plant (NPP), panicle length (PL), number of grains per panicle (NGP), percentage-filled grains (PFG), and thousand-grain weight (TGW), which are useful traits for simultaneous selection for rice yield improvement. A principal component analysis allocated five principal components, accounting for 79.88% of the total variation present in the assessed germplasm collection. Traits that contributed most to variability included NPP, number of tillers/plant (NT), PL, grain yield (GY), and days to 50% flowering (DFL). The genotypes Rangimbili, Gigante, and SARO possess complementary agronomic traits and RYMV resistance, and can be recommended for further evaluation, genetic analysis, and breeding.

Highlights

Rice (Oryza sativa L., 2n = 2x = 24) is an economically important crop in East, Central and West Africa [1] and globally [2]
Significant differences were detected among the genotypes and sites for all the measured agronomic and rice yellow mottle virus (RYMV) disease reaction (RYMVD) parameters, except for days to 50% flowering (DFL)
Significant variation was detected among the assessed genotypes for selection for grain yield and improved RYMV resistance in Tanzania

Summary

Introduction

Rice (Oryza sativa L., 2n = 2x = 24) is an economically important crop in East, Central and West Africa [1] and globally [2]. Rice is a source of 80% of the caloric intake for nearly one billion people in Africa [3]. Africa accounts for nearly 3.0% of the global rice production. About 25% of Africa’s rice requirements have to be met with imports due to the low levels of local production, high levels of population growth, quality preferences, urbanisation and changes in lifestyle [4]. Rice is widely cultivated and commercialized in Tanzania for food security and as a cash crop, ranking second after maize in total production and consumption [5]. The crop is largely cultivated by small-scale farmers cultivating less than one-hectare per household

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