ABSTRACTThe objective of the present study was to determine genetic variability for some agronomic traits and iron toxicity, determine mode of gene action associated with tolerance to iron toxicity and the degree of association between iron toxicity, yield and yield components in rice. The study was carried out using eight (8) parents of rice which comprised of three (3) susceptible and five (5) tolerant to iron toxicity. These were crossed in a half diallel mating design and population generated 28 F1. The parents, F1 population along with two checks were evaluated during the 2017/2018 dry season at an iron toxicity spot in-situ at Edozhigi, Niger state. The experiment was laid in a randomized complete block design and replicated three times. Data were collected and analysed on grain yield, days to 50% flowering, number of tillers, number of leaves, plant height, panicle length, number of seeds per panicle, panicle exertion, number of effective tillers, 1000 grain weight, first iron toxicity score and second iron toxicity score. Results showed highly significance (P<0.01) differences among the genotypes for all the traits which revealed large amount of genetic variability in the parents that could be suitable to initiate selection for crop improvement programme. Results from grain yield of the parents ranged from 2830 kg/ha for FARO 60 to 8210 kg/ha for FARO 57. Grain yield of the variety cross hybrids ranged from 2550 kg/ha for FARO 44 × FARO 61 to 7045 kg/ha for SUAKOKO 8 × CK-21 which out yielded the commercial checks Alh. Baba (4225 kg/ha) and Ewodufagi (4435 kg/ha). General Combining Ability (GCA) and Specific Combining Ability (SCA) mean squares were significant for grain yield, number of tillers, plant height, number of effective tillers and number of seed per panicle under iron toxicity hotspot, indicating the importance of additive and nonadditive gene action for controlling the traits. FARO 52, SUAKOKO 8, CK-21 and CK-43 were good general combiners for grain yield under iron toxicity hot spot conditions. There was preponderance of additive gene effects over non-additive gene effects for all the traits measured indicating that additive gene action was more important in the inheritance of the traits under iron toxicity hotspot. Estimates of variance due to GCA and SCA and their ratios showed preponderance of additive gene effect controlling the adaptive traits for iron toxicity tolerance, estimates of both PCV and GCV revealed low for plant height. In general, PCV values were slightly higher than the GCV values indicating that the traits were less influenced by the environment. High broad sense heritability was recorded for all the traits studied. Significant positive phenotypic correlation existed between grain yield of the F1 hybrids with plant height (r = 0.60**), number of tillers (r = 0.44*), panicle length (r = 0.42*) and number opf effective tillers (r = 0.37*) and negatively correlated with number of leaves (r = -0.45*), panicle exertion (r = -0.64*), first and second iron toxicity scores (r = -0.70*) and ( r = -0.60*), respectively under iron toxicity hotspot. Significant negative correlation was observed between iron toxicity and grain yield (r = -0.41*, r = -0.46*). Number of tillers (r = -0.70**, r = -0.60**), plant height (r = -0.73**, r = -0.77**), panicle length (r = -0.66**, r = -0.69**), number of seeds per panicle (r = - 0.54**, r = -0.41*) and number of effective tillers (r = -0.74, r = -0.65**). The F1 genotype FARO 52 x CK-21 was recommended for more extensive test in regions prone to iron toxicity for adoption and production to alleviate the problem of food insecurity in the country.
PLEASE NOTE
This material is a comprehensive and well-researched project, structured into
(1 - 5) chapters for clarity and depth.
To access the full content:
Click the Download Button Below
Or contact our support team via Call/WhatsApp: 09019904113 for further inquiries.
Thank you for choosing us!
