The objective of this research was to study the diversity and forest structure in fragments with different topographic conditions, relating these components to the tree biomass compartment. Two small fragments of post-disturbance Atlantic Forest, on ravine and flat land areas, were sampled. The numbers effective Hill diversity (qD) and the intensity curves was obtained in both environmental conditions and compared by rarefaction (P = .05). The forest structure was dimensioned using the basal area (BA); diameter of breast height (DBH), total height (H) and tree biomass above ground (AGB), estimated using an adjusted local equation for endangered forests. According to the diversity profiles, it was proved that the ravine has a higher qD for all orders, for both dominant and uncommon species (P < .05). Regarding the forest structure, the ravine showed higher H (greater competitive tendency), a lower investment in DBH (x̅ = 13.05 ± 7.94 cm) in relation to the flat land (x̅ = 38.01 cm ± 17.28 cm), and consequently, low investment in AGB ( x̅ = 306.20 ± 354.08 kg e x̅ = 2336.37 ± 2078.34 kg ravine and flat land, respectively). The present study confirmed the hypotheses of structural change and diversity of the tree component in the different conditions studied, being these factors considered important for the processes of community structuring. These evidences trace back the importance of small forest fragments in ravine conditions and their role in maintaining the Atlantic Forest biodiversity.
The experiment was carried out to evaluate the level of resistance of different genotypes, to study the incidence and severity of bacterial blight, fusarium wilt and phyllody and to select bacterial blight, fusarium wilt and phyllody resistant genotypes across six locations and two years. The experiment was laid out in Randomized Complete Block Designs (RCBD) with three replications across all environments. Assessment was conducted on seventeen sesame genotypes in northern Ethiopia during 2014-2015 main seasons. 75, 70 and 25 percent diseases incidence and 50, 50, 10 percent severity of bacterial blight, fusarium wilt and phyllody was recorded respectively. The assessment result indicated that bacterial blight showed about 62.5, 30, 25, 22.5, 20 and 12.5 combined mean percent diseases incidence and 37.5, 32.5, 25,,15,10 and 7.5 combined mean percent disease severity was recorded in Humera, Kebabo, Gendawuha, Sheraro, Maykadra, Wargiba respectively. Fusarium wilt was recorded from 5%-42.5%, and 7.5 to 25 to combined percent disease incidence and severity was recorded across locations. Phyllody was recorded 2.5 to 17.5%, and 2.5 to 7.5 percent disease incidence and severity respectively. ACC202514, HuRC-4, Abuseffa, HuRC-3, Acc 202300, Acc111824, Acc 27913 and Setit -1 were among the highest resistant (HR) sesame genotypes for phyllody disease. From 0-100% Sesame bacteria blight severity was recorded among genotypes and HuRc-4, HuAC-3 and the standard check (Setit -1) were among the highest resistant (HR) sesame genotypes. Fusarium severity was recorded from 5%-100% range among genotypes. HuRC-2, Acc 227880, Setit -1, Hirhir, HuRC-3, HuRC-4 and ACC202514 were among the resistant (R) sesame genotypes. Whereas Gumero, Acc 202300, Kefif, Acc 111518, Land race Gumero were the highest susceptible (HS) genotypes for fusarium disease across the tested environments and years. From the assessment result indicated that HuRC-4 and HuRC3 genotypes were found resistant to bacterial blight, fusarium wilt and phyllody. Those genotypes could be used for diseases resistant breeding program across different locations. HuRC-4 was evaluated by the national technical committee and it was found relatively resistant and high yielder among the genotypes. Therefore it was released as variety for commercial production to all the tested areas.
A study was carried out to evaluate 40 green gram accessions at Machakos Agricultural Training Centre in Machakos County. The experiment was laid out in a Randomized Complete Block Design with three replications. Data was recorded on eight quantitative agronomic parameters including plant height, number of days to maturity, number of pods per plant, 100 seeds weight and seed yield. The results indicated highly significant (P<0.05) differences in most of the traits studied among the accessions. Accession GBK-022494A had 103 pods per plant as compared to Nylon-2 with 19 pods per plant obtained during the 2011 short rains. Accession GBK-022501A had the highest (4.7 ton ha-1) grain yield followed by GBK-022494A which attained 4.5 ton ha-1. Cluster analysis results indicated that the accessions were divided into two main clusters. One cluster consisted of only one accession- GBK-022494A, while the other cluster had two sub-clusters. Correlation analysis results indicated that pods per plant was significantly and positively correlated with plant height and seed yield, while it was significantly and negatively correlated to pod length and 100 seeds weight. Seed yield was significantly and positively correlated to plant height and number of pods per plant.
This experiment was conducted at the Agricultural Botany experimental field of Sher-e-Bangla Agricultural University (SAU), Sher-e-Bangla Nagar, Dhaka during the period from January to April 2014 to study the effect of sowing times on the morpho-physiological attributes of an exotic (China) hybrid rice variety in Bangladesh. Five treatments were considered regarding 5 sowing dates or transplanting dates viz. (i) S1 = 1stsowing at 1st January 2014; transplanted at 21st January, (ii) S2 = 2nd sowing at 21st January; transplanted at 11th February, (iii) S3 = 3rd sowing at 11th February; transplanted at 3rd March, (iv) S4 = 4th sowing at 3rdMarch; transplanted at 23rd March and (v) S5 = 5th sowing at 23rd March; transplanted at 13th April. Data were recorded on different growth parameters to examine the effect of sowing times on the morpho-physiological attributes of the tested variety. The studied parameters were significantly affected by different sowing times or transplanting times. Results revealed that different parameters regarding morpho-physiological attributes, the seeds of the tested variety sown at 1st January 2014 and transplanted at 21stJanuary (S1) furnished the best results in respect of highest length of panicle at harvest (26.39 cm), and highest number of fertile tillers found from S2= sowing at 21st January; transplanted at 11th February compared to the seedling transplanted on other dates. However, the shortest days of booting, ear emergence and anthesis were found from S5 = 5th sowing 23rd March; transplanted at 13th April. It is revealed that early sowing facilitates tillering and late sowing helps in quick flowering. These findings can be used in further breeding program.
Aim: To investigate the influence of seasonal variations and photoperiodism on the growth phases and cropping cycles of selected rice genotypes in Nigeria
Study Design: The study was a 2 factor factorial experiment laid out in a randomized complete block design (RCBD) with three (3) replicates.
Place and Duration of Study: The trial studies was carried out in four locations, Adim, Assiga, Idomi and Ofodua in 2014 and 2015 crop growing seasons.
Methodology: The experiment for seasonal variation effect was carried out in the field while the experiment on photoperiodism effect was carried in the screen house at Adim. The experiment was a 2 factor experiment. Factor 1 was the rice genotypes which had 4 levels (FARO 44, FARO 12, FARO 15 and FARO 55) while factor 2 which was the different locations also had four levels (Adim, Assiga, Idomi and Ofodua). The experiments were laid out in a randomized complete block design (RCBD), replicated three times with intra and inter – row spacing of 15x15 cm. Plot size of 25 x20 m, was maintained with sampling area of 2 m2. For the natural day length, three seedlings were transplanted into the polyethylene bags containing about 5 kg of soil later thinned to two plants and fertilized with 1g of N, P2O5 and K2O because the initial soil analysis results showed low values of the soil nutrients. The soils were flooded throughout the growth of plants. The experiment for photoperiod was carried out at the World Bank Assisted Rice project in Adim in June, 2014. Three 7 - day old seedlings were transplanted to each polyethylene bag containing 5 kg of soil and fertilized with 2 g each of N, P2O5 and K2O. The plants were subjected to 8, 10, 12, 13, 14 16 and 24 h photoperiods, in a 24 h cycle. The experiment was terminated after 200 days. Their response to different photoperiod treatments were investigated with rice plants in polyethylene bags subjected to varying lengths under artificial light.
Results: High photoperiod - sensitive varieties, showed significant (p<0.05) difference in their maturation periods (crop cycle) when planted at different times (seasons) of the year. The results showed significant (p<0.05) differences in growth phases and crop cycles in the various genotypes as influenced by seasons and photoperiod. The results showed that total growth phase (BVP and PSP) was 86 d for FARO 44 and >130 d for FARO 15. The longest crop cycle of 249 d occurred when plantings were made in January – February with FARO 15 while shortest crop cycle of 78 d occurred when plantings were made in the October - November with FARO 44. In some of the photoperiod - sensitive varieties, exposure of the rice genotypes for 10 h yielded the shortest crop cycle and growth phases for FARO 44 while exposure of varieties to longer photoperiods of 24 h yielded the longest crop cycles for all the varieties when planted in the same month, of different years. These varieties would be unsuitable for planting during the off season (August to September). The results are discussed in light of photoperiod sensitivity of some rice varieties planted at different times of the year.
Conclusion: The results of the study have shown that growth phases and crop cycle of any rice variety is determined by the length of the vegetative reproductive and ripening phases. Since the duration of reproductive and ripening phases is very essential to the crop, it is the vegetative phase that differs and determines the crop cycle of the rice variety. In this test, the crop cycles of Faro 44 and Faro 12 did not vary much with different photoperiods. These test crop varieties (Faro 44 and Faro 12) contrast strongly with those of Faro 52 and Faro 15, in terms of the seasonal variations and photoperiodic screening. The study has been able to bridge the gap in knowledge on seasonal variations and photoperiodism and how these influence rice growth and production in this agro-ecology.