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ThesisItem Restricted Biochemical expression analysis of rice bacterial blight resistance genes, Xa38 and Xa23 at elevated temperature(Punjab Agricultural University, Ludhiana, 2017) Kamboj, Ishwinder; Hunjan, Mandeep SinghBacterial blight of rice caused by Xanthomonas oryzae pv. oryzae (Xoo) is an important disease of rice causing significant yield losses. Currently, there are ten pathotypes of Xoo prevalent in Punjab that has diverse virulence spectra. During the current studies biochemical basis of resistance of two new R genes, Xa38 and Xa23 was showed along with four other genes/ cultivars. The biochemical expression of these six genes/cultivars was studied against five pathotypes of Xoo viz. PbXo-4, PbXo-7, PbXo-8, PbXo-10 and Sgr-1001. These pathotypes showed differential disease reaction on these R genes/ cultivars. It was observed that resistance level offered by Xa38, Xa23 and other R genes/ cultivars in this study is highly correlated with expression of these defence related enzymes viz. Peroxidase, Polyphenol oxidase and Phenylalanine ammonia lyase. It was further observed that expression of Xa38 and Xa23 was not influenced by temperature whereas Xa7 was more effective at high temperature and Xa4 was more effective at lower temperature. No change in aggressiveness of the re-isolated colonies were observed although genetic variations were observed in re-isolated colonies exposed to high temperature and incompatible interactions. The RAPD primer S118 was observed to be highly discriminatory.ThesisItem Open Access Integrated management of root knot nematode in cucumber cultivation(Punjab Agricultural University, Ludhiana, 2017) Harwinder Singh; Dhillon, Narpinderjeet KaurABSTRACT Cucumber (Cucumis sativus) is an economically important crop grown in open as well as in protected cultivation. More and more farmers in Punjab are opting for cucumber cultivation in protected structures. Root knot nematodes have been reported to be associated with cucumber worldwide. The present studies were conducted to know its incidence and severity in polyhouses and open cultivation as well as its management in infested soils. Forty five polyhouses were surveyed from five districts of Punjab viz a viz Ludhiana, Patiala, Bathinda, Sri Muktsar Sahib and Ferozepur. Of these thirty one polyhouses were found to be infested (Frequency of occurrence=68.68 percent). District wise maximum percent infested sites of root knot nematode were reported in Ludhiana (62.72 percent) followed by Ferozepur (50.00 percent), Patiala (39.13 percent), Bathinda (32.00 percent) and Sri Muktsar Sahib (30.00 percent). In open cultivation, thirty fields were surveyed, of which five were found to be infested with root knot nematode. Frequency of occurrence of root knot nematode in open cultivation of cucumber (16.66 percent) was comparatively less than polyhouses cultivation. Decreased infestations in fields were probably due to rotation with rice, fodder or garlic leading to low infestations in successive crop cucumber. The effect of five different inoculum levels of root knot nematode on two varieties of cucumber viz. Punjab Naveen and Pant Sanker revealed significant increase in soil and root population of nematode and decrease in growth parameters as increase in inoculum levels. Of the thirty genotypes of cucumber evaluated against root knot nematode, seven were found to be highly susceptible, twenty one susceptible and two as moderately susceptible. Studies on effect of three different chemicals revealed that Basamid @ 40 g/sqm significantly reduced M. incognita population. In studies on effectiveness of organic amendments and their integration with chemical, mustard cake @ 5 t/ha individually and its integration with Basamid (Basamid @ 20 g/sqm + Mustard cake @ 2.5 t/ha) were found to reduce nematode populations effectively.ThesisItem Open Access Population structure of Albugo candida (Pers.) Kuntze, inciting white rust of rapeseed-mustard(Punjab Agricultural University, Ludhiana, 2017) Chhabra, Gurinder; Sandhu, P.S.White rust caused by Albugo candida is one of the most widespread and destructive disease of rapeseed-mustard causing serious threat to its production. The present studies entitled “Population structure of Albugo candida (Pers.) Kuntze inciting white rust of rapeseed-mustard” were carried out to determine the variation in the pathogen in Punjab state. Isolates of A. candida were collected from different rapeseed-mustard growing areas of Punjab state. A total of 8 districts (Bathinda, Barnala, Faridkot, Muktsar, Mansa, Moga, Ludhiana and Fazilka) were surveyed and 71 isolates were collected from these locations. Disease incidence and severity on different varieties was recorded during crop season 2015-16 and 2016-17. Disease incidence and severity was higher during 2015-16 which ranged from 37.60-64.52 and 21.29-27.45 per cent as compared to 22.52-52.12 and 11.86-22.68 per cent in 2016-17. Highest disease incidence and severity was recorded in Bathinda followed by Mansa and Barnala whereas Fazilka recorded lowest. Highest disease severity was recorded on PBR 91 while lowest on PBR 357. Among the isolates when inoculated on B. juncea var. RL1359, 57 isolates produced similar and stable symptoms, while 14 isolates did not reproduced true to type reaction. Isolates were categorized morphologically on the basis of pustule shape, size and color into three groups viz. AC I, AC II and AC III. Representative isolates were selected from respective groups to study virulence pattern on the basis of disease reaction along with their incubation period, number of pustules, size of pustules, number of sporangia and per cent germination of sporangia. Nine cultivars of the 6 different Brassica sps. were used as host differentials for these isolates. None of the isolates could produce symptoms on B. juncea (RLC 3), B. carinata, B. napus, B. rapa (Toria) TL 15. All the three groups produced symptoms on B. juncea (RL 1359, Varuna, PBR 91) while only group AC III could produce symptoms on B. nigra and B. rapa. Isolates showed considerable variation w.r.t. size of pustules, number of sporangia and percent germination of sporangia with highest in AC III followed by AC I and least in AC II respectively. The incubation period was in range of 7-10 days with 7 on the most susceptible variety RL 1359 and 9-10 days on least susceptible FRG 2 and PT 303 respectively. Genetic characterization was carried out using a set of fourteen SSR primers. With cluster analysis at similarity coefficient of 0.15, isolates were clustered into two main groups with Group 1 and Group 2. Studies on morphological, pathological and genetic level showed that AC III group is most virulent and AC II group is least virulent. Within AC III group, Ac32 and Ac 54 isolates were recorded as more virulent than other isolates and these two isolates were distinct genetically from each other. So it is concluded that there exist some variations among isolates at morphological, pathological as well as genetic level in Punjab.ThesisItem Open Access Evaluation of induced systemic acquired resistance against oomycete pathogens in potato and muskmelon(Punjab Agricultural University, Ludhiana, 2017) Astha; Sekhon, P.S.Oomycetes pathogens; Phytophthora infestans causing late blight of potato and Pseudoperonospora cubensis causing downy mildew in muskmelon are most important foliar diseases, causing significant yield losses. The present study was conducted to reduce fungicide load and work out alternate method for control of these two diseases. Different SAR compounds were tested and exogenous foliar sprays of different conc. of Salicylic acid, Jasmonic acid and Bion (Benzothiadiazole-BTH) @ 50µM, 250µM,500µM, 1000µM and of Beta amino butyric acid of 20 mM, 30mM, 50 mM, 100mM were given for inducing resistance in potato against late blight and in muskmelon against downy mildew. Twenty germplasm lines/varieties of potato and thirtythree germplasm lines/varieties of muskmelon were tested with these four compounds in year 2014, 2015 and 2016. Five lines of potato and eleven lines of muskmelon showed moderate resistance along with better response to SAR elicitors against oomycete pathogens. Concentration of Salicylic acid, Jasmonic acid and Bion @ 500 µM, and Beta amino butyric acid @ 50 mM gave good control of disease. Salicylic acid gave best results with 81.28 per cent disease control followed by Jasmonic acid with 76.23%; whereas Bion and Beta amino butyric acid were almost at par with each other and gave 74 % disease control as compared to control plants. Recommended spray schedule of fungicides gave 93 % disease control, which was at par with disease control given by Salicylic acid and BABA spray schedules in combination with contact fungicides. Protein content of treated muskmelon plant varied from 10.5 to 13.1 mg/g fresh weight compared to 5.4 mg/g fresh weight in control. Similarly, treated potato plants showed 6.4 to 7.7 mg/g fresh weight total protein as compared to 4.0 mg/g fresh weight in control. Induction of proteins and defense enzymes was systemic in nature in response to all the four elicitors. Electrophoretic protein profiling of treated potato and muskmelon plants also confirmed the induction of pathogenesis-related proteins ranging from 15- 75 kDa along with some other proteins. The inducers also stimulated enzymatic activities i.e. β-1,3 glucanase, Peroxidase (POD), Polyphenol oxidase (PPO), Phenylalanine ammonia lyase (PAL) from 26 to 99 % indicating induced resistance in treated potato and muskmelon plants as compared to control. Total chlorophyll and carotenoids also showed spike of 2% to 91 % in response to elicitors. Thus integration of disease tolerance and SA spray schedule resulted in effective and economical control in potato against late blight and in muskmelon against downy mildew.ThesisItem Open Access Identification and Characterization of resistance against downy mildew in Pumpkin (Cucurbita moschata L.) and Snapmelon (Cucumis melo L. var. momordica )(Punjab Agricultural University, Ludhiana, 2017) Khanal, Sita; Sekhon, Parvinder SinghPseudoperonospora cubensis [(Berk and Curtis) Rostovez] an obligate parasite causing downy mildew of snapmelon and pumpkin, that can survive and reproduce on living host tissue resulting in significant yield losses. Fourty six and thirty three accessions of snapmelon and pumpkin were screened against P. cubensis in year 2015-2016 and 2016-2017 cropping season respectively. Plants were inoculated at optimum level of sporangial suspension (4.0 x 104 sporangia per ml) to create downy mildew. Out of fourty six accessions of snapmelon, three were resistant having incidence in the range of 20-30 per cent and rest were moderately resistant, moderately susceptible, susceptible and highly susceptible. However, in case of pumpkin, thirteen accessions were resistant having incidence in the range of 3-6 per cent and rest were moderately resistant, moderately susceptible, susceptible and highly susceptible. Significant mean maximum disease index was observed in snapmelon accession SM 2013-7 and minimum in accession MC 2013-4. Similarly, in case of pumpkin, mean maximum disease index was observed in accession BN 364 and minimum in accession P-111. Antioxidant enzymes activity was estimated spectrophotometrically from the leaf samples. The data pertaining to the activity of antioxidant enzymes revealed significant differences among the accessions showing different reaction against P. cubensis. Higher activity of antioxidant enzymes were observed in resistant followed by moderately resistant accessions whereas; activity gradually declined among susceptible and highly susceptible accessions of snapmelon and pumpkin. Negative correlation was obtained between antioxidant enzyme activity and disease development suggesting possible involvement of these enzymes in imparting disease resistance against downy mildew in sanpmelon and pumpkin. Improving the genetic resistance of snapmelon and pumpkin to downy mildew through introgressive breeding could be an effective way to control this disease. The narrow genetic base of modern snapmelon and pumpkin accessions and a few sources of resistance make downy mildew resistance an important objective in snapmelon and pumpkin breeding programs. Therefore, the identification of new sources of resistance is desirable.ThesisItem Open Access RESPONSE OF COTTON GENOTYPES TO RELATION TO INDUCTION OF RESISTANCE AGAINST COTTON LEAF CURL DISEASE(PAU Ludhiana, 2013) Ritu Raj; P S, SekhonThe present study was conducted to check the response of different American cotton cultivars namely RS 921, LH 2076, PIL 8, Ankur 3028 BGII and a desi cotton variety LD 694 to Jasmonic acid (JA) and Salicylic acid (SA) in induction of resistance against cotton leaf curl disease (CLCuD). Different cotton cultivars were grown in pots under screen cages. At four to six leaf stage potted plants of different cotton cultivars were treated with different concentration of JA and SA i.e. 50 μM, 100 μM, 150 μM, 200 μM respectively and water sprayed plants of corresponding genotypes served as control. Quantification of proteins was done using spectrophotometric method from the leaf samples collected at 24, 48, 72, 96 hrs and a week after treatment with JA and SA. Application of JA and SA resulted in the induction of proteins 24 hrs after treatment. After a week interval at 150 μM concentration of JA maximum protein induction of 19.9 mg/g fr. wt., 16.7 mg/g fr. wt., 19.6 mg/g fr. wt., 15.0 mg/g fr. wt. and 14.4 mg/g fr. wt. was recorded in RS 921, LH 2076, PIL 8, Ankur 3028 BGII and LD 694 respectively whereas, in case of SA 200 μM concentration showed maximum protein induction i.e 10.6 mg/g fr. wt., 9.3 mg/g fr. wt., 9.9 mg/g fr. wt., 9.0 mg/g fr. wt., 8.1 mg/g fr. wt. in RS 921, LH 2076, PIL 8, Ankur 3028 BGII and LD 694 respectively. In the induction of proteins JA was found to be more effective than SA. Electrophoretic study of cotton cultivars treated with 150 μM of JA and 200 μM of SA revealed the induction of Pathogenesis-related (PR) proteins ranging from 15-45 kDa along with some other proteins as well. JA and SA applied at different concentrations affected the CLCuD incidence and severity when inoculated with viruliferous whiteflies (Bemesia tabaci) in screen cages. Lower disease incidence as well as disease index was observed with JA when applied @ 150 μM and SA @ 200 μM. Disease incidence was 37%, 30%, 30% and disease index was 48%, 40%, 40% in RS 921, LH 2076, Ankur 3028 BGII at 150 μM concentration of JA whereas, at 200 μM SA disease incidence was 48%, 36%, 34% and disease index was 57%, 50%, 50% respectively in above mentioned cultivars and in their respective control values for disease incidence and disease severity were quite high. So, JA at 150 μM and SA at 200 μM concentration was found to be most effective in lowering the disease. Latent carry over detection of symptomless plants treated with 150 μM of JA and 200 μM of SA through PCR amplification using DNA specific primers confirmed the presence of virus in all the tested cotton cultivars except LD 694 which signified that PR proteins does not eliminate virus. JA and SA application resulted in imparting tolerance with the induction of PR proteins but does not lead to complete resistance against the disease.ThesisItem Open Access RESPONSE OF COTTON GENOTYPES TO JASMONIC ACID IN RELATION TO INDUCTION OF RESISTANCE AGAINST COTTON LEAF CURL DISEASE(PAU Ludhiana, 2013) Raj, RituThe present study was conducted to check the response of different American cotton cultivars namely RS 921, LH 2076, PIL 8, Ankur 3028 BGII and a desi cotton variety LD 694 to Jasmonic acid (JA) and Salicylic acid (SA) in induction of resistance against cotton leaf curl disease (CLCuD). Different cotton cultivars were grown in pots under screen cages. At four to six leaf stage potted plants of different cotton cultivars were treated with different concentration of JA and SA i.e. 50 μM, 100 μM, 150 μM, 200 μM respectively and water sprayed plants of corresponding genotypes served as control. Quantification of proteins was done using spectrophotometric method from the leaf samples collected at 24, 48, 72, 96 hrs and a week after treatment with JA and SA. Application of JA and SA resulted in the induction of proteins 24 hrs after treatment. After a week interval at 150 μM concentration of JA maximum protein induction of 19.9 mg/g fr. wt., 16.7 mg/g fr. wt., 19.6 mg/g fr. wt., 15.0 mg/g fr. wt. and 14.4 mg/g fr. wt. was recorded in RS 921, LH 2076, PIL 8, Ankur 3028 BGII and LD 694 respectively whereas, in case of SA 200 μM concentration showed maximum protein induction i.e 10.6 mg/g fr. wt., 9.3 mg/g fr. wt., 9.9 mg/g fr. wt., 9.0 mg/g fr. wt., 8.1 mg/g fr. wt. in RS 921, LH 2076, PIL 8, Ankur 3028 BGII and LD 694 respectively. In the induction of proteins JA was found to be more effective than SA. Electrophoretic study of cotton cultivars treated with 150 μM of JA and 200 μM of SA revealed the induction of Pathogenesis-related (PR) proteins ranging from 15-45 kDa along with some other proteins as well. JA and SA applied at different concentrations affected the CLCuD incidence and severity when inoculated with viruliferous whiteflies (Bemesia tabaci) in screen cages. Lower disease incidence as well as disease index was observed with JA when applied @ 150 μM and SA @ 200 μM. Disease incidence was 37%, 30%, 30% and disease index was 48%, 40%, 40% in RS 921, LH 2076, Ankur 3028 BGII at 150 μM concentration of JA whereas, at 200 μM SA disease incidence was 48%, 36%, 34% and disease index was 57%, 50%, 50% respectively in above mentioned cultivars and in their respective control values for disease incidence and disease severity were quite high. So, JA at 150 μM and SA at 200 μM concentration was found to be most effective in lowering the disease. Latent carry over detection of symptomless plants treated with 150 μM of JA and 200 μM of SA through PCR amplification using DNA specific primers confirmed the presence of virus in all the tested cotton cultivars except LD 694 which signified that PR proteins does not eliminate virus. JA and SA application resulted in imparting tolerance with the induction of PR proteins but does not lead to complete resistance against the disease. Key words: Cotton, Cotton leaf curl disease (CLCuD), Jasmonic acid (JA), Salicylic acidThesisItem Open Access VARIABILITY IN Albugo candida (Pers.) Kuntze CAUSING WHITE RUST OF RAPESEED-MUSTARD(PAU Ludhiana, 2011) Yash Pal; P. S., SandhuABSTRACT White rust caused by Albugo candida (Pers.) Kuntze is a serious threat to the production of oilseed Brassica crops in India and around the world. Variation occurs w.r.t. infection of the pathogen on different species of oilseed Brassicas which encouraged us to carry out the studies on “Variability in A. candida (Pers.) Kuntze causing white rust of rapeseed-mustard”. Survey was conducted in different locations (Bathinda, Mansa, Barnala, Faridkot, Muktsar, Sangrur, Ferozepur, and Ludhiana) of Punjab to estimate disease incidence and severity of the disease. The disease incidence and severity of white rust ranged from 44.39-59.36 and 21.92-27.83 per cent, respectively, in different locations of Punjab. A total of 52 isolates were collected from different locations and varieties. These isolates were classified into three groups (AC-I, AC-II and AC-III) on the basis of pustule size, pustule shape and germination of sporangia. Three representative isolates of each group were tested on twelve differential host cultivars (B. juncea, B. nigra, B. napus, B. carinata, B. oleracea, B. tournifortii, B. rapa var. Toria, B. rapa (Brown sarson), B. rapa (Yellow sarson), Raphanus sativus, Sinapis alba and Eruca sativa) of rapeseed and mustard. AC-III group has most virulent and AC-II group showed least virulence based on disease reaction, incubation period, latent period, pustule size, shape, number of pustules per leaf and number of sporangia per pustule. Further, within AC-III group, Ac6 isolate was observed as more virulent than other isolates of same group. Hence, it is concluded that morphological and pathological variation exists in A. candida population from Punjab.ThesisItem Open Access MANAGEMENT OF BOTRYTIS BLIGHT (Botrytis gladiolorum Timm.) IN GLADIOLUS THROUGH CULTURAL AND CHEMICAL MEANS(PAU Ludhiana, 2011) SATYA PRAKASH PANDEY; Premjit SinghThe incidence and severity of Botrytis blight of gladiolus (Botrytis gladiolorum Timm.) and yield of the crop were the minimum in the early- and late-planted crop, as compared to the recommended planting date, i.e. 15th October. Closer spacing resulted in higher incidence and severity of the disease but the corm yield was recorded to be higher in the closer spacing as compared to the wider spacing. Plant spacing of 20x 20 cm was found to be suitable. Incidence and severity of the disease were also found to be high in the un-weeded control. Pre-emergence application of weedicide Stomp at 650 ml/ac, alone, and in combination with one manual weeding at six-leaf stage of the crop, recorded low incidence and severity of the disease and also registered high corm and cormel yields. Two manual weedings, at three- and six-leaf stages of the crop, respectively, also gave good results. Among the non-systemic fungicides, Dithane M-45 showed the best result under in vitro conditions as it completely inhibited spore germination of the pathogen at 100μg/ml, while Kavach and Antracol completely inhibited spore germination at higher concentrations of 500μg/ml. Among the systemic-fungicides, Stroby was the most effective fungicide, followed by Flint and Bavistin. Germ tube length of the fungus was found to be the minimum in Kavach and Dithane M-45. The fungicides Stroby and Flint were found to be the most effective fungicides against Botrytis blight of gladiolus under field conditions. The fungicides Kavach and Dithane-M-45 also showed very promising efficacy.