AGRO-MORPHOLOGICAL CHARACTERIZATION AND GENETIC DIVERSITY OF RICE LANDRACES IN SAVANNA ZONES OF NIGERIA

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Date
2019-03
Authors
MUHAMMAD, Hadiza Usman
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Abstract
This research was conducted to evaluate the agro-morphological characteristics of rice landraces and their genetic diversity in savanna zones Nigeria. A total of seventy rice landraces from eighteen northern states were utilized for the study. The landraces were sown in polythene bags packed with loamy soil (8kg). A complete randomised design layout with three replicates was adopted. Twenty seven agro-morphological traits (15 qualitative and 12 quantitative agronomic traits) were evaluated based on the internationally accepted standard evaluation system for rice. The genetic diversity of the landraces was also determined based on 21 SSR primers using standard protocol. Results obtained revealed a highly significant variability (p < 0.01) among the landraces for all the qualitative and quantitative traits. The cluster analysis for the qualitative traits grouped the landraces into five cluster groups at 60% similarity coefficient. Variability studies indicated that the estimates of phenotypic coefficient of variation (PCV) were higher than genotypic coefficient of variation (GCV) for all the agronomic traits evaluated. The PCV and GCV are respectively highlighted in grain yield per plant (80.37 and 77.83g), number of filled grains per panicle (78.78 and 76.62), number of panicles per plant (27.18 and 26.51), number of total grains per panicle (24.98 and 24.05) and number of leaves per plant (22.74 and 20.46). The agronomic traits measured showed high broad sense heritability (74.5% - 99.3%) with the exception of days to germination (58.9%). The high yielding landraces were WACOT (9600kg/ha), Yar china-KB (858.18kg/ha), Jamila PLT (589.09kg/ha) and Yar Zaiti (560kg/ha). Significant (p < 0.01) positive correlation for number of filled grain per panicle (r = 0.94) and number of total grain per panicle (r = 0.53) with grain yield was obtained. At 91 % similarity coefficient, the seventy rice landraces were grouped into three cluster groups based on the agronomic traits evaluated. Landraces from cluster group one had highest mean values for number of leaves per panicle (20.33), number of panicles per plant (20.29), number of filled grains per panicle (63.56), number of total grains per panicle (86.45) and grain yield per plant (8.26g). Landraces in cluster group two had highest mean value for hundred seed weight (2.61g) while landraces in cluster group three showed highest mean values for plant height (71.96cm) and panicle length (22.82cm). Genetic diversity of the rice landraces based on 21 SSR primers detected alleles that ranged from 3 to 6 with an average of 4 alleles per primer. Polymorphic information content ranged from 0.34 to 0.79 with an average of 0.45. The neighbor joining tree based on SSR markers grouped the landraces into 4 cluster groups at 95 % similarity coefficient. In conclusion, although there exist morphological diversity in the rice landraces present in Nigeria savanna zones, however, these landraces are genetically closely associated. This could have resulted from the admixture of landraces over time. Agro morphological diversity obtained could have resulted due to environmental factors. The information from this study could be very useful in identification and selection of suitable parents for use in breeding programmes.
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A DISSERTATION SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY, ZARIA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF MASTER OF SCIENCE DEGREE IN BIOLOGY DEPARTMENT OF BIOLOGY, FACULTY OF LIFE SCIENCES AHMADU BELLO UNIVERSITY, ZARIA, NIGERIA
Keywords
AGRO-MORPHOLOGICAL CHARACTERIZATION,, GENETIC DIVERSITY,, RICE LANDRACES,, SAVANNA ZONES, NIGERIA,
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