Efficacy of Different Plant Extracts on Fusarium Wilt caused by Fusarium oxysporum in Chillies under Field Condition

Chilli (Capsicum annum L.) is vegetable crop belongs to family Solanaceae. It is an important source of vitamin A and C. In developing countries most of chilli diseases are due to fungal attack and cause severe losses in yield. Fusarium wilt of chilli which is caused by Fusarium oxysporium f. sp. capsici is an important disease of chilli which causes heavy yield losses in Pakistan. Present research was planned to evaluate effect of different concentrations of plant based phyto-extracts against Fusarium wilt on chilli pathogen under natural field condition. In research trails the leave extract of Euclayptus globulus, Cassia fistula, Moringa oleifera, Vachellia nilotica and Azadirachta indica were evaluated in the management of fusarium wilt. These trails were planned under Randomized Complete Block Design (RCBD). Three concentrations of above mentioned leaf extracts were used 20%, 30% and 40%. At 40% Eucalyptus, Moringa and Azadiracta gave best results with maximum reduction in Fusarium wilt. While all other extracts results were also satisfactory. So we can use these botanicals as a control for this disease in chilli. Keywords: Capsicum annum, Fusarium wilt, Fusarium oxysporium, Phyto-extracts.

Screening of Tuberose Cultivars against Leaf Spot (Alternaria polyanthi) and its Management

Background: Tuberose flower has been found to be affected by various fungal and viral diseases which affect growth and cause loss in flower yield. Among them, leaf spot incited by Aternaria polianthi is an important fungal disease in tuberose. The incidence of the disease is common in the both single and double-type tuberose varieties due to prevalence of high rainfall and humid conditions. During survey it was found that the disease incidence was increasing gradually causing economic losses in Assam. Methods: The field trial was carried out during kharif seasons (2015 -18) to test the efficacy of six fungicides against leaf spot of tuberose (Var. Local single petal) caused by Alternaria polyantha. Four sprays with fungicides at an interval of seven days starting from the first appearance of the disease symptom were done. Per cent disease incidence (%) with growth parameters were recorded one week after the last spray. Another field experiment for screening the resistant genotypes was conducted using 11 tuberose genotypes during kharif seasons (2016-17 and 2017-18). Result: Eleven tuberose cultivars (Bidhan Ranjani-1, Bidhan Ranjani-2, Arka Nirantara, GK-TC-4, Prajwal, Phule Rajani, Local Single, Local Double, Vaibhav, Suhashini and Shringer) were screened against leaf spot caused by A.polyanthi under natural field condition. None of the cultivars were found to be immune or resistant, while three cultivars viz., GK-TC-4, Bidhan Rajani-1 and Arka Nirantara showed moderate resistant reaction with recorded per cent disease incidence of 16.11, 18.17 and 18.71, respectively. Spraying with azoxystrobin, difenoconazole and a combo fungicide consisting of iprodione (25%) + carbendazim (25%), at 0.1% recorded lowest per cent disease incidence of 7.91, 9.83 and 11.85% compared to control (33.62 PDI) with per cent disease reduction of 70.59%, 64.61% and 76.31%, respectively.

Study about GAU 4: A New High Yielding Ymv Resistant Urdbean Variety

GAU 4 is a high yielding, YMVD resistance variety developed through selection from germplasm maintained (GP No. 6) at ARS, AAU, Jabugam, Dist : Chotta Udaipur, Gujarat and tested as JAUG 2 in trial. JAUG 2 recorded 21.03 and 24.48 per cent higher yield (961 kg/ha) over the checks T 9 and GU 1, respectively under middle Gujarat. In kharif season, JAUG 2 recorded 1005 kg/ha seed yield which was 19.08 and 23.92 per cent higher over T 9 and GU 1, respectively under middle Gujarat. In summer, JAUG 2 recorded 864 kg/ha seed yield which was 22.21 and 23.42 per cent higher over T 9 and GU 1, respectively under middle Gujarat. The proposed genotype JAUG 2 has semi-erect plant type and medium maturity duration. It has deltoid leaf shape, green hairy pod with 5-7 seeds per pod, dark black and medium seed size (seed index.:4-5 g). On quality point of view, this genotype contains 24.66% protein, 55.58% total carbohydrate, 4.77% total soluble sugar, 0.946% phenol and 8.89 mg/100g flavonoid, which is comparable to check varieties T 9 and GU 1. In mineral contains 49.97 Fe, 29.28 Zn and 7.29 Cu mg kg-1 which is higher than both check varieties viz., T 9 and GU1. The genotype JAUG 2 is found resistant to Yellow Mosaic Disease under natural field condition as compared to check T 9 and GU 1. The special feature of newly develop variety is medium maturity, semi-erect plant type, hairy pod, dark black, drum shape seed, resistant to YMD with higher yield.

Field screening of rice (Oryza sativa L.) genotypes for resistance to bacterial leaf blight (Xanthomonas oryzae pv. oryzae) disease

Rice is the most important crop in Nepal followed by maize and wheat in terms of area (1.4 million ha), production (5.15 million) and productivity (3.5 mt/ha). Bacterial leaf blight (BLB), caused by Xanthomonas oryzae pv. oryzae is considered to be the most widespread and destructive disease of rice in both irrigated and rainfed environments in Nepal. Use of host plant resistance is the most feasible and economical way to combat this disease. However, breakdown of resistance of a variety often occurs after few years of release due to genetic adaptation of the pathogen. Regular screening of the genotypes is utmost for developing the resistant genotypes. Considering the point, this investigation effort has been made to screen the rice genotypes against BLB under natural field condition at Khajura, Banke during 2018 and 2019. In the study, plants were assessed by measuring disease severity (percentage of leaf diseased) and area under the disease progress curve (AUDPC). Differences in resistance among the rice genotypes were observed in both of the tested year. Among the screened 150 rice genotypes during 2018, 6 genotypes scored resistant (R), 81 moderately resistant (MR), 59 moderately susceptible (MS) and 4 susceptible (S) to BLB. Whereas, in 2019, among the tested 315 rice genotypes, none of the genotypes were resistant, 183 MR, 131 MS and 1 S to BLB disease. This showed that the tested genotypes were composed of different genetic background.

Screening of sugarcane genotypes against Top Borer (Scirpophaga exerptalis Walker) infestation

Fourty sugarcane genotypes with different period of maturity were evaluated against top borer (Scirpophaga excerptalis Walker) infestation under natural field condition during 2018 and 2019 at National Sugarcane Research Program, Jeetpur, Nepal. The experiment was conducted in alpha-lattice design under natural condition of infestation using Co 0238 as susceptible check. Based on the incidence, 26 genotypes were categorized as less susceptible, eleven genotypes were found moderately susceptible to S. excerptalis. However, among less susceptible genotypes lowest incidence of 3.11 percent was recorded in genotype CoS 8432. Whereas, highest incidence of 25.24 percent was recorded in highly susceptible genotype, CoSe 98255BD 24. Most of the cane genotypes were found low to moderately susceptible, having 5 to 20% incidence of the pest. Whereas, some of the varieties, namely CoH 160 (21.22%), CoSe 95255 BD 24 (25.24%) and BO 150 (22.02%) were found highly susceptible. The mechanism responsible for host plant resistance against top borer is not studied in this experimentation. The study in these aspects is to be conducted to explore the mechanisms of host plant resistance for using these resistant genotypes for breeding purpose.

Variability Studies in Melon (Cucumis melo.L) F2 Population of Kashi Madhu x COHB38 for Powdery Mildew Resistance

The present investigation was carried at College of Horticulture, Bengaluru. Evaluation of melon F2 population (Kashi Madhu X COHB38) was conducted during rabi 2016 for resistance to powdery mildew disease under natural field condition. Percent Disease Index (PDI) and AUDPC (Area Under Disease Progress Curve) value was calculated to assess the reaction of F2 (Kashi Madhu X COHB38) segregating population of melon along with the parents (COHB38 and Kashi Madhu) and F1. Based on PDI for powdery mildew disease, 152 F2 plants were classified into different categories. Twenty five F2s were resistant (0-25% PDI), 27 were moderately resistant (25.1-40% PDI), 88 were susceptible (40.1-60% PDI) and 12 F2s were highly susceptible (>60% PDI). Among 152 F2 plants, F2 -34 was found to be highly resistant with zero PDI and zero AUDPC value (no disease) followed by F2- 46 and 92 with PDI of 13.89 % and 16.11 % and 46.94 and 55.00 AUDPC value, respectively. The PDI of the disease showed a continuous distribution from highly resistant to highly susceptible phenotypes, without showing any typical segregation pattern. Int. J. Appl. Sci. Biotechnol. Vol 7(4): 407-413

Improvement in anaerobic germination potential and grain yield of rice (oryza sativa) through seed priming

A field experiment was conducted during the dry season of 2014 and 2015 at National Rice Research Institute (NRRI), Orissa, India, (20.5ºN, 86°E, and 23.5 meters above mean sea level). Seed priming was employed to enhance the anaerobic germination potential in two near isogenic rice lines (IR64 and IR64-Sub1). Under natural field condition, oxygen concentration in floodwater never dropped to zero. It varied from 3.0 to 5.2 mg L-1. Seed priming with calcium peroxide and seed soaking with water followed by sun drying showed greater beneficial effects as compared to potassium nitrate. Seed priming with sodium peroxide found deleterious. Cultivar IR64-Sub1 responded well due to seed priming as compared to cultivar IR64 under submergence. To improve anaerobic germination potential in rice, seed soaking with water followed by sun drying found economicalas compared to other methods of seed priming as this technique was not linked with additional investment in chemicals and was more environments friendly. SAARC J. Agri., 17(1): 37-48 (2019

Molecular tagging of botrytis grey mould disease in chickpea

Validation of two primers TA144 and TR29 for their linkage with botrytis grey mould resistance gene was studied in twenty genotypes of chickpea including resistant (GL10006) and susceptible (DCP92-3) checks. The genotypes were also scored for disease reaction under natural exposure at hot spot location. Molecular analysis with primers TA144 and TR29 showed polymorphic bands in GL10006 and DCP92-3. Therefore, it can be concluded that the primers are linked with resistance gene. The genotypes that showed amplicons with both the primers at same or nearby positions of resistant check were HK-2, HK-4, BG-1003, KAK-2 and GNG-1969 and indicated as resistant or moderately resistant ones. The above genotypes were also found resistant under natural field condition. Thus both the primers TA144 and TR29 showed good correlation with phenotypic evaluation in most of the genotypes studied. In future, more number of primers nearby the resistance gene(s) can be tried for their contribution towards overall disease reaction.