Field Evaluation of Heat Stress-Resilient Maize Hybrids for Improved and Stable Maize Production in Nepal

In recent years, National Maize Research Program (NMRP) aimed a paradigm shift from open-pollinated varieties (OPVs) towards hybrid maize to achieve self-sufficiency in maize for food, feed, and hybrid seed within the country. In this mission, it is necessary to identify and deploy high-yielding stress-resilient maize hybrids that can cope with climate change effects, including heat stress. Under the project “Heat Tolerant Maize for Asia (HTMA)”, NMRP introduced the hybrids that performed better in previous years in different environments from International Maize and Wheat Improvement Center (CIMMYT) Hyderabad for multilocation on-farm testing. Fifteen genotypes were evaluated at two locations, two sites in Madi, Chitwan, and one in Ghorahi, Dang, along with Rampur Hybrid-8 as a heat-tolerant check, and RML-86/RML-96 and RML-95/RML-96 as normal checks. Randomized complete block design (RCBD) was used with three replicates during the spring of 2016/17. Likewise, another 20 and 18 promising hybrids were demonstrated during the winter of 2016/17 and 2017/18, respectively, in different hybrid growing pockets considering a site – a replication. Grain yield and yield attributing traits at all locations were recorded. From the across-site data analysis, selected heat-tolerant hybrids from the experiment were CAH1432, ZH15405, ZH141592, and CAH1715 which were statistically at par with promising normal hybrid RML-86/RML-96 and superior to already released heat-tolerant Rampur Hybrid-8. In 2016/17, ZH138098, ZH1620, and VH121062 were farmers’ preferred heat-tolerant hybrids. In 2017/18, Rampur Hybrid-10, ZH141592, CAH1715, and ZH15440 were preferred by farmers. The selected bestbet are taken forward for official release/registration followed by commercialization through a public-private partnership with Nepali seed companies/cooperatives. SAARC J. Agric., 19(1): 27-43 (2021)

Potency of Three Botanical Oils Against the Aphis Craccivora Koch (Homoptera: Aphididae) Nymphs Under Laboratory Conditions

Botanicals are promising and attractive alternatives for pest management. In the present study, three botanical oils namely neem (Azadirachta indica), karanja (Pongamia pinnata) and mehogony (Swietenia mahagoni) were tested against the nymphs of Aphis craccivora Koch to evaluate the toxic and repellent effects under laboratory conditions (25 ± 5oC, 65-75% RH). Four concentrations (0.5, 1.0, 1.5, and 2.0%) along with control were maintained with distilled water and tween-20 was used as emulsifier. Leaf dipped method were used for insect bioassay. Insect mortality was recorded at 24, 48 and 72 hours after intervals while repellency was carried out at 2 hours after intervals upto 10th hours and the collected data were analyzed through MSTAT-C program. Results indicated that all the tested oils had toxic and repellent effects against the A. craccivora nymphs. Among the tested botanical oils, no significant difference was observed in terms of mortality over treatment time. But significant difference was noticed over level of concentrations exerted by the botanical oils. The average highest mortality (28.62%) was recorded by the application of mehogony oil whereas neem oil showed the lowest mortality (27.21%) against the A. craccivora and the mortality was directly proportional to the level of concentrations and hour after treatment (HAT). Probit analysis showed the lowest LD50 values of mehogony oil which revealed the highest toxic effect against the nymph of bean aphid. The highest repellent effect (77.33%) was found in mehogony oil (repellent class IV) among all the botanical oils applied. On the contrary, neem (57.33%) and karanja (55.00%) oils belonged to the same repellent class that is repellent class II. Although all the tested botanical oils evaluated showed toxic and repellent effects but mehogony oil performed as the best potent oil against the nymphs. We therefore suggested using the mehogony oil for the management of bean aphid. SAARC J. Agric., 19(1): 139-154 (2021)

Effect of Ethephon and Packaging Practices On Ripening of Mango cv. Maldah

The present research was conducted on two factor Completely Randomized Design (CRD) with eight treatments and three replications. A set of experiments were carried out to evaluate the effect of postharvest ethephon treatment and packaging on ripening of mango cv. Maldah. The treatments consisted of ripening agent i.e., ethephon and control treatment under different packaging condition i.e., fiber with hole, fiber without hole, plastic with hole and plastic without hole. The result revealed that different packaging condition and ripening agents influenced the ripening behavior of mango. The highest TSS (15.26), sugar-acid ratio (23.66) and juice content (126.05) were recorded with fiber (without hole) and the lowest TSS (12.60), sugar-acid ratio (9.01) and juice content (116.05) with plastic (without hole). The highest TA (1.44) was recorded with plastic (without hole) and the lowest (0.66) with fiber (without hole). Similarly, the highest BT (2.83) was recorded with fiber (with hole) and the lowest (1.66) with plastic (without hole). Firmness, sweetness, TSS and juice content were the highest with the interaction effect of fiber bag (without hole) and ethephon treatment. In conclusion, mango fruits with ethephon treatment packed in fiber bag (without hole) enhances quality and ripening of mango whereas under controlled condition and without hole plastic packaging mangoes had low quality performance in terms of physio-chemical properties. SAARC J. Agric., 19(1): 155-163 (2021)

Comparative Evaluation of Onion Germplasm (Allium Cepa L.) Of Bangladesh for Physical And Antioxidant Properties

Determination of antioxidant activity is one of the key elements for understanding the biological properties of a widely used spice onion (A. cepa). In contrast, physical properties help understand the textural quality of onion necessary for postharvest operations of sorting and grading in particular. Considering the physicochemical importance of onion, the present study focused on the determination of physical attributes and antioxidant content of the onion germplasm in Bangladesh using visual methods and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, respectively. The five-onion germplasms (BARI Piaz-2, BARI Piaz-3, BARI Piaz-4, BARI Piaz-5, Faridpuri Vati) collected from selected onion growers of the Department of Agricultural Extension (DAE) of the southwestern part of Bangladesh were used as treatments for physicochemical analysis at the Horticulture laboratory of the Agrotechnology Discipline, Khulna University, Khulna, Bangladesh during the period from February to August 2019. The laboratory study was laid out in Completely Randomized Design (CRD) with three replications. Most of the physical characteristics of onion were highest in germplasm-1 than those of the other germplasm tested. The results showed that the DPPH free radicals were scavenged by all onion germplasm extracts in a concentration-dependent pattern. The highest IC50 value (238.10 ppm) was noticed in germplasm-3 and the lowest in germplasm-5 (161.29 ppm) with no statistical difference from germplasm-4 (172.41 ppm). The lower IC50 value indicating that onion germplasms-5 and -4 extracts were more potent in scavenging free radicals than the other onion germplasms. Thus, the low IC50 value facilitated the germplasm-5 and -4 to be enriched with antioxidant compounds significantly in higher amounts than the others. SAARC J. Agric., 19(1): 113-123 (2021)

Impact of Training on Livestock Technology Transfer for Rural Poor Farmers Livelihood Improvement in Bangladesh

The study was conducted to evaluate the impact of training facilitated by Nuton Jibon Livelihood Improvement Project (NJLIP) under Social Development Foundation (SDF) for transfer livestock technologies and livelihood improvement for rural poor farmers in Bangladesh. A total of 650 farming households were selected by baseline survey during January 2018 to June 2018.The training and non-training beneficiaries were primary level educated and their family size (4.52) was little lower than the national average (4.9). Average age was 36.73 and 35.12 years for training and non-training farmers, respectively. The rate and amount of loan was found higher with respondent received training than without training. Adoption rate of technologies was higher than the level of idea on the concept of housing, feeding, breeding and marketing. The training beneficiaries improved knowledge and skill on feeding, management and health care of livestock and poultry. Training and demonstration are considered two strong tools for adoption and dissemination of livestock technology. Herd and flock size was increased by training beneficiaries than non-training beneficiaries. Beneficiaries having training on various IGAs have expanded their land and asset possession to a greater extent compared to non-training beneficiaries. Housing and sanitation condition of training beneficiaries were higher than non-training beneficiaries. Increased annual income of training and non-training households was 19.43% and 13.30% where income from different IGAs of livestock was 32.19% and 14.53%, respectively. Livestock were not extremely price sensitive but more sensitive on non-price factors logistic support like institutional support, quality of input and availability of input. Thus, training was treated as vital tools for transfer livestock technologies to influence the poor farmer’s livelihood improvement of training household than non-training household. SAARC J. Agric., 19(1): 223-235 (2021)

Yield and Yield Contributing Attributes Of Potato as Influenced by Vermicompost And Seed Tuber Size

Low yield is crucial bottleneck for potato production in Bangladesh. The application of vermicompost may enhance the yield of potato. The experiment was consisted of two factors, i.e., Factor A: - Vermicompost level (Vm1-4): Vm1: 0 t ha-1, Vm2: 3 t ha-1, Vm3: 6 t ha-1 and Vm4: 9 t ha-1; Factor B:- Tuber size (T1-5): T1: 5-10 g, T2: 10-20 g, T3: 20-30 g, T4: 30-40 g and T5: > 40 g. The experiment was conducted in a split-plot design with three replications. Vermicompost had significant effect on most of the yield contributing parameters investigated under present study. Results revealed that yield parameters increased with increasing vermicompost level irrespective of tuber size. Among the twenty (20) treatment combinations, vermicompost at the rate of 9 t ha-1 with tuber size > 40 g produced the maximum yield (31.33 t ha-1) that was 53.53 % higher than that of control with 3273.01 $ of monetary advantage. Therefore, present study suggests that potato growers may use vermicompost for increasing yield of potato in Bangladesh. SAARC J. Agric., 19(1): 71-79 (2021)

Morpho-Biochemical Characteristics of Brinjal Germplasms Affect the Abundance And Infestation of Jassid

The tropical vegetable, brinjal is cultivated throughout the year in Bangladesh but the crop is infested by a number of insects including jassid. This study investigated the effects of different biophysical and biochemical characteristics of twelve brinjal germplasms on the abundance and infestation of jassid. The experiment was conducted during September 2018 to March 2019 in Gazipur, Bangladesh with twelve brinjal germplasms namely BD-7320, BD-7328, BD-9952, BD-10154, BD-10158, BARI Begun-1, BARI Begun-4, BARI Begun-5, BARI Begun- 6, BARI Begun-7, BARI Begun-8 and BARI Begun-9. The incidence of jassid was recorded from 3rd December to 26th March, and the lowest population was found on BARI Begun- 6. Among the biophysical traits, plant height, number of branch and leaf per plant, and leaf area exerted significant positive correlation; whereas trichome on lower and upper surfaces of leaf, spine per stem and leaf showed significant negative correlation with the abundance of jassid. On the other hand, moisture, reducing sugar, total sugar and protein content of the leaves and fruits, chlorophyll content of the leaves exerts significant positive correlation but ash and pH contents of the leaves and fruits were negatively correlated with the abundance of jassid. Jassids showed the lowest level of leaf infestation on BARI Begun-6, which could be for further analysis to develop jassid resistant brinjal. SAARC J. Agric., 19(1): 81-91 (2021)

Assessment of Genetic Diversity of 62 F4 Population of Rapeseed (Brassica Napus L.) Through Multivariate Analysis

Rapeseed (Brassica napus L.) is the best one in respect of oil production. It is the order of the day to take better steps for production and quality improvement of our local cultivars. Broadening of genetic diversity in spring oilseed Brassica napus L. (AACC, 2n = 38), canola is important for continued improvement of this crop. Sixty-two genotypes in F4 generation of Brassica napus L. were evaluated to assess genetic diversity based on randomized complete block design with three replications at the experimental field of Sher-e-Bangla Agricultural University, Dhaka. Different Multivariate analyses were performed to classify 62 genotypes. On the basis of cluster analysis, all the genotypes were classified in five clusters. The cluster IV comprised the maximum number (19) of genotypes followed by same in cluster II (18). The cluster I and V comprised 10 and 9 genotypes respectively. The lowest number of genotypes was present in cluster II. The highest inter-cluster distance (10.309) was observed between the cluster I and IV and the genotypes of these clusters involved in hybridization may produce a wide spectrum of segregating population. The lowest inter-cluster distance (3.513) was observed between the cluster III and IV. The inter-cluster distances were larger than the intra-cluster distances. Considering cluster distance, inter genotypic distance and other agronomic performance G3, G4, G24, G35 and G51 might be suggested for future breeding program. SAARC J. Agric., 19(1): 15-25 (2021)

Screening of Mango Rootstock For Saline Tolerance

An experiment was conducted at Fruit Tree Improvement Project, Fruit Tree Improvement Programme, Bangladesh Agricultural University-Germplasm Center (FTIP, BAU-GPC), Bangladesh Agricultural University (BAU), Mymensingh during the period of April 2020 to June 2020 to study the performance of selected mango rootstocks for the saline area. The two-factor experiment consisted of four mango rootstock varieties such as V1 = BAU Aam-9, V2 = BAU Aam-6, V3 = BAU Aam-4 and V4 = Amropali and six salinity treatments namely control S1 = 0 dSm-1, S2 = 4 dSm-1, S3 = 8 dSm-1, S4 = 10 dSm-1, S5 = 12 dSm-1 and S6 = 14 dSm-1. The experiment was conducted following randomized complete block design with three replications. Results revealed that rootstock line and salinity levels had significant influences on various rootstock characters viz. length of rootstocks, number of leaves and percent rootstocks success and survivability. In case of varietal effect, the highest number of leaves (32.44) found in BAU Aam-6 and the lowest number of leaves was recorded in Amropali (22.55) at 90 days after transplanting. The longest rootstock length observed in 90 DAT which (54.83 cm) found in BAU Aam-9and shortest rootstock recorded in Amropali (47.94 cm). The highest survivability (51.44%) was recorded in BAU Aam-9 and the lowest survivability recorded in Amropali (33.88%). In case of salinity treatments, the highest survivability (95.83%) was recorded in control and the lowest survivability (0.00%) recorded in 14 dsm-1 at 90 DAT. Interaction of rootstock varieties and different salinity treatments showed significant variation on the length leave and survivability of rootstocks at 90 DAT. The maximum number of rootstock leaves recorded in V2S2 (46.33) and lowest number of leave recorded in V4S6 (7.66). The highest rootstock length was found in V1S3 (78.00 cm) and lowest in V1S2 (21.66 cm). The highest Survivability (100 %) observed in V1S1, V1S2, V2S1, V2S2 and V4S1. From the above mentioned it can be said BAU Aam - 9 and BAU Aam – 6 rootstock varieties performed best from 0-8 dSm-1 salinity. The overall salinity tolerance was graded as follows: BAU Aam - 9>BAU Aam – 6> BAU Aam-4>Amropali rootstock line. SAARC J. Agric., 19(1): 93-102 (2021)

Use of Immunostimulants for Fish Health Management in Mymensingh District Of Bangladesh

Immunostimulants have been used as a prospective substance against several disease events in aquaculture, although subsequent impact is not clearly explored yet. The present study was conducted to investigate the use of immunostimulants for fish health management in Mymensingh district of Bangladesh. Questionnaire survey was performed with a total of 40 fish farmers and 20 chemical and drug retailers. Altogether, 41 immunostimulants under 7 different categories including glucans and polysaccharides, vitamins, minerals, vitamin-mineral premixes, enzymes, nucleic acids and plant extracts were reported. ACI, Eon, Acme, Square, Renata and SK+F were noticed as the prominent sources among 24 listed companies in this study. The most frequently used immunostimulants were recorded as Megavit-aqua (88.75%), Multivitamin (87.5%), Aqua-boost (87.25%), Eskalina (83.25%) and Eon fish grower (82.5%). Farmers in this study mentioned about improved health condition with lower average disease incidence (29.3%) and reduced mortality (65.35%) in fish after application of immunostimulant. The findings of this study will be useful to perform further research regarding the efficacy and impacts of a wide range of immunostimulants used in aquaculture of Bangladesh. SAARC J. Agric., 19(1): 237-248 (2021)