Morphological and physiological characters affecting flower drop and fruit set of tomatoes at high temperatures

Summary Seven tomato cultivars and lines were studied under high temperature conditions. Fruit set varied between 77.3% in the heat tolerant cv. Hotset, 62% in cv. Gamad and 16.3% in the most sensitive cv. Hosen-Eilon. The characters contributing to low fruit set were bud drop, splitting of the antheridial cone, style exsertion and reduction of the quantity and/or functionality of the gametes. Employing the above characters as criteria for selection, fruit set of an F₄ line, phenotypically similar to the sensitive parent, was improved to 63.1%. Improved fruit set, 87.6%, was also obtained in an F₁ hybrid between Hotset and Gamad. The importance is discussed of various easily recognizable flower components contributing to satisfactory fruit set under high temperatures and their possible use in breeding is elaborated.     

Resistance to multiple leaf spot diseases in wheat

Tan spot (TS), Stagonospora nodorum blotch (SNB), and Septoria tritici blotch (STB) are three major leaf spot diseases of wheat worldwide. Host plant resistance (HPR) is one of the main components in the management of these diseases in wheat. The objective of this study was to identify new sources of resistance to TS (races 1 and 5), SNB, and STB. A total of 164 wheat genotypes developed by the International Maize and Wheat Improvement Center (CIMMYT), Mexico were individually evaluated for TS, SNB and STB in spring and fall of 2006 in the greenhouse. Two experiments were conducted in a randomized complete block design with three replicates. Each replicate consisted of 164 wheat genotypes planted in cones with three seedlings/genotype in each cone and disease reaction was assessed for each race or pathogen at the two- to three-leaf stage. Based on the disease reactions, three wheat genotypes were resistant to both TS and SNB, while 13 genotypes were resistant to TS and STB. Similarly, 13 genotypes were resistant to both SNB and STB. In addition, four wheat genotypes were highly resistant to TS, SNB, and STB. These results suggest that the resistant genotypes identified in this study possess high levels of resistance to multiple leaf spot diseases and could be valuable sources for wheat improvement programs.     

Incentives and Community Participation in the Governance of Community Forests in Nepal

Increased participation of local users in decision-making about forests and gaining benefits from these forests are major goals of the community forestry program in Nepal. However, there is a lack of real participation in community forest governance amongst users, particularly by poor and marginalised members. By employing a mixed-method approach, this research explores the issue of participation in the governance of community forests, and in particular the role of incentives in increasing participation. A partial least square approach is undertaken to link the participation indicators to the various incentives. Access to benefits, enforcement of legal property rights and social cohesion through building of local institutions are identified as the key influential incentives that determine the effective participation of users in community forest governance. Other incentive—including income supplements, community infrastructure development or payment for environment services—are insufficient to counter the opportunity cost of participation, and hence have a weak but still significant influence on users’ decisions to participate. Power inequality due to socio-cultural norms, together with poor economic capabilities and weak bargaining power, could undermine the meaningful participation of poor and disadvantaged groups in the governance of community forests, unless the community forestry institutions are strengthened in order to be able to deal with the issues of inequitable access and restricted opportunities at the local level.     

Zinc delivery to plants through seed coating with nano-zinc oxide particles

In India, zinc (Zn) has been recognized as the fourth most important yield-limiting nutrient after nitrogen (N), phosphorus (P) and potassium (K). Supplementing the zinc (Zn) requirement of agricultural crops through water soluble zinc sulfate ZnSO₄ fertilizer is a costly management option whereas, utilization of ZnO (water insoluble and a cheaper material) as a source of Zn could be an alternative cost effective option to encourage farmers for wider adoption. In this present investigation, in order to supply the requisite amount of Zn to the plants, a protocol has been developed to coat the seeds of maize (Zea mays L.), soybean (Glycine max L.), pigeon pea (Cajanas cajan L.) and ladies finger (Abelmoschus esculentus L.) with microns scale (<3 µm) and nano-scale (<100 nm) ZnO powder at 25 mg Zn/g seed and at 50 mg Zn/g seed. Different Zn sources, ethyl alcohol, and crude pine oleoresin (POR) were used for coating of seeds. The germination test carried out with coated and uncoated seeds indicated better germination percentage (93–100%) due to ZnO coating as compared to uncoated seeds (80%). Pot culture experiment conducted with coated seeds also revealed that the crop growth with ZnO coated seeds were similar to that observed with soluble Zn treatment applied as zinc sulfate heptahydrate (ZnSO₄·7H₂O) (at 2.5 ppm Zn) which is evident from the periodic SPAD reading taken after 20, 25, 30 and 45 days after sowing. Application of Zn through different sources also enhanced the auxin indole-3-acetic acid (IAA) production in plant roots, which subsequently improved the overall growth. The most important advantage of seed coating with ZnO (both micron/nano-scale) is that it did not exert any osmotic potential at the time of germination of the seed, thus, the total requirement of Zn of the crop can be loaded with the seed effectively through nano-scale ZnO particle.     

Effects of stocking density of Labeo rohita on survival, growth and production in cages

Labeo rohita (139.92 ± 0.76 mm/24.33 ± 0.45 g) was reared for 92 days in floating square cages (10 m² area, 1.5 m height) in a pond (2 ha) at six stocking densities (5, 7.5, 10, 15, 20 and 25 fish m^?2) each with 3 replicates. Fish were fed daily once in the morning with rice polish and groundnut oil cake (1:1) in dough form at 3 % of the total body weight. Survival ranged from 96 to 100 % in different stocking densities. Final average body weight, average body weight gain, mean daily body weight gain and SGR decreased (P < 0.05) with increasing stocking density. Conversely, final biomass, biomass gain and FCR increased (P < 0.05) with increasing stocking density. The highest growth rate of fish could be achieved up to 60 days at 5 fish m^?2 and 92 days at other densities. The reduced growth rate at 10–25 fish m^?2 for 60 days of culture indicated that stress is related to size and density of the fish, suggesting that utmost care is required to reduce the stress at high densities. Maximum production and profit was observed at the highest stocking density. Non-lethal levels of water and soil qualities at different sites (cage premises, and 20 and 200 m away from cage area) suggested that cage aquaculture could be done safely covering 0.9 % of pond area. Production of advanced fingerlings in cages was found a viable alternative to their culture in pond.     

Efficacy of mulching, irrigation and nitrogen applications on bottle gourd and okra for yield improvement and crop diversification

An on-farm irrigation trial conducted on the upland of Chitwan valley of Nepal evaluated the amount and frequency of irrigation as well as the effect of nitrogen fertilizer and straw mulch applications on the performance of bottle gourd and okra vegetables. The experiment was laid out on split-split-plot design with fertilizer as main-plot factor, frequencies of irrigation as sub-plot factor, and amount of irrigation as sub-sub-plot factor. Data analysis revealed that frequency and amount of irrigation had a significant interaction effect on the number of nodes that emerge before the opening of the first flower in bottle gourd. Likewise, a significant effect of mulching was observed on the number of primary branches (P = 0.05). Number of nodes and primary branches both contributed to higher production of bottle gourd. Results also indicated that frequent application of higher amount of irrigation to bottle gourd could lead to reduced water productivity and suffer from yield losses. In the case of okra, low level of nitrogen application (30 kg N ha⁻¹) with low but daily watering had significantly higher yield (1,365 g plot⁻¹) than from higher level of nitrogen application (90 kg ha⁻¹) (P = 0.01). Interaction effect of all factors was also significant (P = 0.05) on the fruit yield of okra which implied greater value of smaller irrigation to contribute to increased returns to farmers by improving production level of okra in this area of Nepal     

On-Farm Diversity Assessment and Participatory Varietal Evaluation of Cold-Tolerant Rice in Mid-Hills of Nepal

Journal of Crop Science and Biotechnology - Drawing upon consequentially growing food insecurity in mid-hills attributed to poor adoption levels inter alia inflicted by narrow range of locally...     

Penetrance of gene I for Fusarium resistance in the tomato

Tomato seedlings were inoculated, from one to ten days after emergence, with the tomato Fusarium wilt fungus race 1. The penetrance of gene I for Fusarium resistance in the homozygous resistant variety Homestead 24 was almost complete. In the F₁ (Ii) between Homestead 24 and the susceptible Marmande penetrance was incomplete and ranged between 66.3% and 100% in different experiments. The age of seedlings at time of inoculation did not affect the final percentage of diseased plants while it influenced the nature and the time of appearance of disease symptoms. Possible consequences of incomplete penetrance for the resistance of F₁ hybrids are discussed.     

Evaluation of curcumin and copper acetate against Salmonella Typhimurium infection,intestinal permeability,and cecal microbiota composition in broiler chickens

Background: Interest in the use of natural feed additives as an alternative to antimicrobials in the poultry industry has increased in recent years because of the risk of bacterial resistance. One of the most studied groups are polyphenolic compounds, given their advantages over other types of additives and their easy potentiation of effects when complexes are formed with metal ions. Therefore, the objective of the present study was to evaluate the impact of dietary supplementation of copper acetate(CA), curcumin(CR), and their combination(CA-CR)against Salmonella Typhimurium colonization, intestinal permeability, and cecal microbiota composition in broiler chickens through a laboratory Salmonella infection model. S. Typhimurium recovery was determined on day 10 post-challenge by isolating Salmonella in homogenates of the right cecal tonsil(12 chickens per group) on Xylose Lysine Tergitol-4(XLT-4) with novobiocin and nalidixic acid. Intestinal integrity was indirectly determined by the fluorometric measurement of fluorescein isothiocyanate dextran(FITC-d) in serum samples from blood obtained on d 10 post-S. Typhimurium challenge. Finally, microbiota analysis was performed using the content of the left caecal tonsil of 5 chickens per group by sequencing V4 region of 16 S rRNA gene.Results: The results showed that in two independent studies, all experimental treatments were able to significantly reduce the S. Typhimurium colonization in cecal tonsils(CT, P 0.0001) compared to the positive control(PC)group. However, only CA-CR was the most effective treatment in reducing S. Typhimurium counts in both independent studies. Furthermore, the serum fluorescein isothiocyanate dextran(FITC-d) concentration in chickens treated with CR was significantly lower when compared to PC(P = 0.0084), which is related to a decrease in intestinal permeability and therefore intestinal integrity. The effect of dietary treatments in reducing Salmonella was further supported by the analysis of 16 S rRNA gene sequences using Linear discriminant analysis effect size(LEfSe)since Salmonella was significantly enriched in PC group(LDA score 2.0 and P 0.05) compared to other groups. In addition, Coprobacillus, Eubacterium, and Clostridium were significantly higher in the PC group compared to other treatment groups. On the contrary, Fecalibacterium and Enterococcus in CR, unknown genus of Erysipelotrichaceae at CA-CR, and unknown genus of Lachnospiraceae at CA were significantly more abundant respectively.Conclusions: CR treatment was the most effective treatment to reduce S. Typhimurium intestinal colonization and maintain better intestinal homeostasis which might be achieved through modulation of cecal microbiota.     

Genetic structure of Phaeosphaeria nodorum populations in the north-central and midwestern United States

Stagonospora nodorum blotch, caused by Phaeosphaeria nodorum, is considered one of the most destructive foliar diseases of wheat in the United States. However, relatively little is known about the population biology of this fungus in the major wheat-growing regions of the central United States. To rectify this situation, 308 single-spore isolates of P. nodorum were analyzed from 12 populations, five from hard red spring wheat cultivars in Minnesota and North Dakota and seven from soft red winter wheat in Indiana and Ohio. The genetic structure of the sampled populations was determined by analyzing polymorphisms at five microsatellite or simple-sequence repeat (SSR) loci and the mating type locus. Although a few clones were identified, most P. nodorum populations had high levels of gene (H(S) = 0.175 to 0.519) and genotype (D = 0.600 to 0.972) diversity. Gene diversity was higher among isolates collected from spring wheat cultivars in North Dakota and Minnesota (mean H(S) = 0.503) than in those from winter wheat cultivars in Indiana and Ohio (H(S) = 0.269). Analyses of clone-corrected data sets showed equal frequencies of both mating types in both regional and local populations, indicating that sexual recombination may occur regularly. However, significant gametic disequilibrium occurred in three of the four populations from North Dakota, and there was genetic differentiation both within and among locations. Genetic differentiation between the hard red spring and soft red winter wheat production regions was moderate (F(ST) = 0.168), but whether this is due to differences in wheat production or to geographical variation cannot be determined. These results suggest that sexual reproduction occurs in P. nodorum populations in the major wheat-growing regions of the central United States, and that geographically separated populations can be genetically differentiated, reflecting either restrictions on gene flow or selection.