Evaluation of M6 Ofada Rice Mutant Selections and Parents for Grain Physico-Chemical and Nutritional Characters

Rice consumers are becoming more conscious of the varieties they consume in terms of nutritional quality. Selection for quality improvement would benefit from induced variability as innate sources are becoming exhausted. This study was carried out to assess the extent of improvement of rice grain quality yield for the benefit of the farmers and the consumers. Two Ofada rice varieties (FUNAABOR 1 and FUNAABOR 2) were irradiated with 60Co gamma rays to elicit variation towards selection for grain improvement in 2013. Individual seed selections from different treatment levels in M1 and subsequent generations were harvested and replanted for advancement to M6 generation. Harvested seeds from selected promising M6 mutants and parents were subjected to physical, chemical and nutritional analysis.  Analysis of Variance (ANOVA) was applied to data to generate character overall mean and variance estimates from which heritability estimates were computed. Means of the different mutants were compared with parents using Duncan Multiple Range Test (DMRT). Ofada rice mutants and parents varied significantly for all the studied grain traits. The mutants and parents had long grains (6.6mm - 7.1mm). Mutant, OG13602 _100 had high values for amylose content (20.01%), followed by OG13608_300 (19.47%). The two mutants (OG13602_100 and OG13608_300) respectively also recorded the highest values for crude protein (6.41% and 6.28%), fat (3.94% and 3.81%), fibre (2.14% and 2.05%), and ash content (3.92% and 3.71%). Overall, the entries clustered into two groups along the parental lines and present opportunities for hybridization. High heritability with concomitant high genetic advance was recorded for amylose, ash and moisture content. All selected promising Ofada rice mutants and parents had long grains. Specifically, mutants OG13602_100 and OG13608_300 which expressed superior amylose, protein, fat, fibre and ash contents present opportunities for further improvement for grain quality. The significant variability of the studied traits revealed additional gains from further selection

Response of rice genotypes to salinity under hydroponic conditions

The experiment was aimed at assessing the response of 30 rice genotypes to different levels of salinity using NaCl concentration as salt stress at early seedling stage under hydroponic conditions. The experiment was replicated three times in a Completely Randomized Design for two years. The 30 rice genotypes evaluated for root length, fresh root weight, dry root weight, shoot length, fresh shoot weight, dry shoot weight, seedling biomass and shoot/root length ratio. The four salinity treatments/levels (0, 4, 6 and 12 dS/m) significantly affected the response of the 30 rice genotypes for all the traits evaluated. The interaction between salinity treatments and the genotypes was significant for all traits except fresh root weight, shoot length and dry shoot weight. The genotypic response revealed reduction in performance as the salinity level increases for all the traits, 10 genotypes were tolerant at all salinity levels. The most affected seedling trait due to salinity stress was seedling biomass at 6 dS/m (54.84%) and was expressed by genotype IR29 (susceptible check), followed by ROK 24 at 12 dS/m (54.43%). Eight rice genotypes; CK73, ITA212 (FARO 35), ITA222 (FARO 36), OG0315, OG250315, OW0315, TOG 5681 and Pokkali (Tolerant Check) were classified highly tolerant by both Stress Tolerance Index (SST) and Stress Susceptible Index (SSI), while FARO 61 (NERICA L – 34) and IR72 were moderately tolerant. These rice genotypes have good potentials for further salt tolerance breeding.Keywords: salt stress, genotypes, seedling traits, tolerance index, susceptible inde

Assessment of 60Co gamma radiation on early phenological stages of two generations of OFADA rice

Traditional Ofada rice varieties from South-West, Nigeria is preferred for its unique taste, aroma and massive potential for export but has low yield. Based on this background, two Ofada rice varieties, FUNAABOR 1 and FUNAABOR 2 were irradiated to create genetic variability as it affects vegetative traits. Seeds from the varieties were exposed to nine levels of 60Co gamma irradiation (0, 50, 100, 150, 200, 250, 300, 350 and 400 Gy). The seeds were nursed for 30 days before M1 seedlings were transplanted into a well tilled soil in a two factorial RCBD with three replicates. Selections from M1 plants were used to establish M2 plants generation. The results revealed diverse effects of 60Co gamma irradiation treatments on different plant vegetative traits. The establishment rates of M1 Ofada rice population were unaffected (p > 0.01) by increasing gamma irradiation from 0 to 300 Gy but decreased at 350 Gy. Above 300 Gy, tiller numbers, plant height, lodging incidence, leaf number, leaf length and leaf angle decreased significantly when compared with control (p < 0.01) in both generations (M1 and M2). Moderately tillered (10 tillers), tall plant (116.9 cm) obtained from 350 dosage rate recorded highest grain weight of 7.8 g per panicle. High phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) promoted by the irradiation dosages in M1 selection indicate the extent of environmental influence. High broad sense heritability observed from leaf number, leaf angle, leaf length, leaf blade colour, basal leaf sheath colour and grain weight per panicle shows possibility of rapid genetic improvement of these characters through selection

Characterization of host tolerance to Striga hermonthica

One of the most promising control options against the parasitic weed Striga hermonthica is the use of crop varieties that combine resistance with high levels of tolerance. The aim of this study was to clarify the relation between Striga infestation level, Striga infection level and relative yield loss of sorghum and to use this insight for exploring the options for a proper screening procedure for tolerance. In three pot experiments, conducted in Mali (2003) and The Netherlands (2003, 2004), four sorghum genotypes were exposed to a range of Striga infestation levels, ranging from 0.0625 to 16 seeds cm−3. Observations included regular Striga emergence counts and sorghum grain yield at maturity. There were significant genotype, infestation and genotype × infestation effects on sorghum yield. The relation between infestation level and infection level was density dependent. Furthermore, the relation between Striga infection level and relative yield loss was non-linear, though for the most resistant genotype Framida only the linear part of the relation was obtained, as even at high infestation levels only moderate infection levels were achieved. The results suggest that for resistant genotypes, tolerance can best be quantified as a reduced relative yield loss per aboveground Striga plant, whereas for less resistant genotypes the maximum relative yield loss can best be used. Whether both expressions of tolerance are interrelated could not be resolved. Complications of screening for tolerance under field conditions are discussed

Yield performance, heritability and interrelationships in some quantitative traits of “tatasai” pepper (Capsicum annum L.)

Yield performance, heritability, correlation and path analysis were studied in 5 genotype of `tatasai' pepper for 2 years in a randomized complete block design and replicated three times. L 5962-2. PL-2289 and U-Kimba had the highest fresh fruit yield (1.215, 1.183 and 1.087 t/ha respectively). Broad sense heritability ranged from 34.7% in yield to 85.3% for number of fruit/plant. Genotypic coefficient of variation was high for number of fruit/plant (30.1%), yied (22.9%) and percent fruit set (17.0%). Fresh fruit yield was positive and higly correlated with all the traits studied except plant height. Path analysis revealed that percent fruit set, total number of leaves and number of fruit set, total number of leaves and number of fruit/plant had the highest positive direct effect on fresh fruit yield, while plant height had low negative direct and indirect effect on fruit yield. Key words: Yield, heritability, correlation, path analysis, tatasi pepper

Genetic, Phenotypic and Environmental Variances and Character Associations in Kenaf

Kenaf ( Hibiscus cannabinus L.) is an important food and livestock feed in Nigeria, which has hitherto been ignored in genetic improvement. Data obtained from evaluating fifty-seven diverse genotypes of Kenaf for two years in Samaru in the Nigerian Guinea Savanna ecological zone were used to study genetic variability and interrelationships between seed yield and its components. The results indicate a preponderance of genetic components of variance for seed yield, plant height, number of seeds per pod and 1000 seed weight indicating that selection for these traits should result in heritable improvements. Seed yield was found to be positively and significantly correlated with plant height, number of seeds per pod and 1000 seed weight. Significant and positive correlations were also obtained between plant height and number of capsules per plant and between 1000 seed weight and number of seeds per pod. The path-coefficient analysis indicates that number of seeds per pod and 1000 seed weight had the highest direct effects on seed yield. It is suggested that for a meaningful seed yield improvement programme, efforts should be directed towards the best balance between number of seeds per pod and 1000 seed weight.Kenaf ( Hibiscus cannabinus L.) est une importante nourriture et un aliment pour les animaux au Nigeria, qui a été littéralement ignoré dans l'amélioration génétique. Les données récoltées durant l'évaluation de cinquante sept diverses gênes de Kenaf pour deux ans en Samaru dans la zone écologique de la savane guinéenne du Nigeria étaient utilises pour étudier la variation génétique et l'interrelation entre le rendement en graines et ses composantes. Les résultats indiquent une prépondérance des composantes génétiques dans la variance du rendement en graines, la taille de la plante, nombre de graines par gousse et le poids de 1000 graines indiquant une sélection pour ces races conduirait à une amélioration de l'héritage. Le rendement en grains était positivement et significativement corrélé avec la taille de la plante et le nombre des capsules par plante et le poids de 1000 graines, et nombre de graines par gousse. L'analyse des coefficients des corrélations indique que le nombre de graines par gousse et le poids de 1000 graines avaient l'effet direct le plus élevé sur le rendement en graines. Il est recommandé que des efforts soient orientés vers l'équilibre entre le nombre des graines par gousse et le poids de 1000 graines, pour que l'impact du programme d'amélioration de rendement soit significatif

Comparative analysis between maturity traits, yield components and yield of Tattasai Pepper under contrasting conditions.

This work reports on the results of comparative traits involving 10 tattasai pepper (Capsicum annuum L.) grown for 2 years under contrasting conditions of wet and dry season as treatment in randomized complete block design and replicated three times. The result showed non significant effect of years, year x treatment and year x genotype for all the traits. Mean reduction ratio (MRR) signifies delayed expression of maturity traits from -12.1% for days to maturity to - 47% for number of leaves at first flowering under dry season, while MRR for yield and yield components was high and positively expressed under wet season. Correlations indicate that improving yield of tattasai pepper requires simultaneous selection of yield, yield components and number of leaves at first flowering. Correlated response revealed that fruit weight, fruit/plant and percent fruit set are the largest contributors to yield under both seasons and years. Key words: Mean reduction ratio, correlated response, pepper, dry and wet seasons