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ThesisItem Open Access Gene scouting for rust(s) resistance in wheat germplasm(Punjab Agricultural University, Ludhiana, 2018) Sandeep Singh; Jaspal KaurDuring the Rabi crop season of the year 2016-17, six hundred and seven (607) wheat germplasm lines were evaluated in the field and found sixty six lines resistant to stripe rust, three hundred thirty six lines resistant to leaf rust and thirty four lines resistant to both stripe rust and leaf rust. In the second year (2017-18), the wheat germplasm was evaluated against different pathotypes of Puccinia striiformis tritici (Pst) (238S119, 110S119, 46S119 and 78S84) and P. triticina (Pt) (77-5 and 77-9) at seedling stage. From seedling reaction test it was observed that fifty six (56) lines and one hundred and ten lines (110) possess resistance against all the pathotypes of Pst and Pt tested respectively. All the test wheat lines were categorized into different clusters based on final rust severity (FRS), area under disease progress curve (AUDPC), relative area under disease progress curve (rAUDPC) and coefficient of infection (CI). Fifty two (52) lines were highly resistant to stripe rust and one hundred seventy one (171) lines were highly resistant to leaf rust and remaining lines showed different reaction based on the particular range of slow rusting parameters. Genotypes which showed resistance either to stripe rust or to leaf rust were further evaluated against mixture of Pst pathotypes (238S119, 110S119, 46S119 and 78S84) and individually against 110S119 and 46S119. For leaf rust evaluation was done by using mixture of Pt pathotypes (77-5, 77-9, 104-2 and 12-2) and 77-5 and 77-9 in isolation. NILs carrying known APR genes and susceptible checks for also used for comparison purpose under the field conditions. The results of the present study revealed that fifty two lines has resistance against most prevalent pathotypes of stripe rust in Punjab (238S119, 110S119, 46S119 and 78S84) and one hundred seventy one (171) lines have resistance to mixture (77-5, 77-9, 104-2 and 12-2) pathotypes of Pt. Reaction on NILs showed that Yr1, Yr5, Yr10, Yr15, Yr24, Yr26, Yrsp, Yr31, Yr51, Yr47, Yr57, Yr63 are effective against most prevalent pathotypes of stripe rust in Punjab and Lr2a, Lr2b, Lr8, Lr19, Lr22a, Lr23, Lr(27+31), Lr45, Lr51, Lr53, Lr57, Lr58, Lr76 are effective against leaf rust pathotypes. For deployment of resistance sources, total 40 crosses were made. Eleven lines resistant to stripe rust were crossed with PBW621 and twenty nine lines resistant to leaf rust were crossed with HD3086. F1 and F2 plants obtained were tested separately against stripe rust and leaf rust. From the disease reaction of majority of F1 and F2 populations it was concluded that resistance in these lines is controlled by single dominant gene against both stripe and leaf rust.ThesisItem Restricted Epidemiology and management of Stemphylium blight of garlic(Punjab Agricultural University, Ludhiana, 2018) Salaria, Pooja; Amarjit SinghStemphylium blight of garlic caused by Stemphylium vesicarium (Wallr.) Simmons is commonly found in garlic growing areas of Punjab. The lesions colonized by S. vesicarium was round to elliptical. The most effective media for growth and sporulation of S. vesicarium was V8 juice agar media. Maximum disease severity was recorded in Moga district whereas minimum in Ludhiana. Leaf wetness duration of minimum 8 hrs is necessary for the infection but maximum disease developed at 24 hrs of leaf wetness duration. The optimum temperature for the disease development was 25ºC whereas it was nil at 15ºC. The disease severity increases with the increase in age of the plant and it was found maximum on 105 days old plants. The garlic plants sown on 6-16 November exhibited minimum disease severity. No genotype exhibited resistance to disease under natural and artificial epiphytotic conditions. The performance of PG-17 and PG-18 was better in comparison to other genotypes tested against Stemphylium blight under artificial epiphytotic conditions. Neem oil and Neem extract can be used as an alternative to Mancozeb 75% WP for eco-friendly management of the disease. These can be useful in devising integrated management strategy for Stemphylium blight of garlic.ThesisItem Open Access Etiology and management of root rot complex of groundnut (Arachis hypogaea L.)(Punjab Agricultural University, Ludhiana, 2018) Sekhon, Amritpal Singh; Sandhu, P.S.Isolations made from root rot complex samples of groundnut collected from groundnut growing areas of Punjab revealed that the five fungal genera namely Aspergillus niger, A. flavus, Mcarophomina phaseolina, Rhizoctonia solani and Sclerotium rolfsii were found associated with the root rot complex disease. Among the species associated with root rot complex, the incidence of A. niger was highest. The maximum incidence of root rot complex was found in Hoshiarpur district (21.52 %), followed by Sangrur (21.35 %). Among the five cultivars found on the farmer’s field, only SG-99 showed moderately resistance reaction to the disease while other four cultivars namely M-522, Malika, TAG-24 and TG 37A showed moderately susceptible reaction. Among the 29 isolates of A. niger, 18 isolates were with light yellow, 6 isolates white and 5 isolates with pale yellow colour of mycelium. Effect of sowing date on the disease development was studied at three locations namely PAU, Ludhiana, RRS Ballowal Saunkhri and KVK, Kheri. Among the total seven sowing dates, 15th March was most suitable for SG-99 and 30th March for M-522. The early sowing of virginia type groundnut (M-522) was more sensitive to the temperature compared to spanish type (SG-99). Among the fungicides tested using poisoned food tehcnique, tebuconazole gave maximum inhibition of mycelial growth of A. niger followed by azoxystrobin and Sprint (carbendaim + mancozeb). In paper towel method, the seed treatment with Sprint (carbendazim 25 + mancozeb 50) gave maximum seed germination and seedling vigour followed by Vitavax power (carboxin 37.5 + thiram 37.5). Total six fungicides were evaluated for their effectiveness against root rot complex disease under field conditions with 13 treatments. Among them, seed treatment with tebuconazole plus two sprays of tebuconazole found to be highly effective in controlling the disease followed by seed treatment with azoxystrobin plus two sprays of azoxystrobin and seed treatment with Vitavax power plus two sprays of tebuconazole. The seed treatment with tebuconazole plus two sprays of tebuconazole (0.15 %) gave maximum pod yield (3267 kg/ ha in SG-99 and 2811 kg/ ha in M-522) followed by seed treatment with azoxystrobin plus two sprays of azoxystrobin (0.1 %).ThesisItem Restricted Prevalence and management of leaf spots of sorghum(Punjab Agricultural University, Ludhiana, 2018) Lambay, Gursimran Kaur; Upasana RaniThe present investigation was conducted at Forage Research Farm and Pathology Laboratory of Department of Plant Breeding and Genetics, PAU, Ludhiana during Kharif 2012. Leaf spots were prevalent in Ropar, Hoshiarpur, Jalandhar, Ludhiana, Moga and Faridkot but intensity was more in Hoshiarpur and Ropar. Grey leaf spot was widely and severely distributed than zonate leaf spot and anthracnose. Fungi associated with leaf spots were identified as Cercospora sorghi causing grey leaf spot, Gloeocercospora sorghi causing zonate leaf spot and Colletotrichum graminicola causing anthracnose of sorghum. The fungi associated with these leaf spots has also been detected as part of seed mycoflora and might play role in primary infection. Development of leaf spots revealed that grey leaf spot appeared in first week of July, whereas zonate leaf spot and anthracnose appeared in field in second week of August and end of July respectively with maximum per cent disease index (PDI) of 39.67 (grey leaf spot), 20.42 (zonate leaf spot) and 11.75 (anthracnose) towards the end of the season. Relative humidity and rainfall were positively correlated, whereas temperature was significantly and negatively correlated with develoopment of leaf spots. Grey leaf spot was predominant on all dates of sowing but intensity of all the leaf spots was high in timely and the late sown. Of 119 germplasm accessions, 7 (94001 A, NS 1008-A, SSG 226, SSG 241, SSG 253, SGL 244 and SGL 98-12) showed multiple disease resistance against these leaf spots. Under in vitro conditions, Emisan @ 2.5g/kg seed showed the lowest infection by different mycoflora, whereas under in vivo conditions seed treatment with Emisan @ 2.5g/kg seed and Bavistin @ 3g/kg seed recorded minimum leaf spot intensity in both forage and grain crops. These treatments also showed increase in yield.ThesisItem Open Access Etiology of stem gummosis and leaf blight of bottle gourd (Lagenaria siceraria) in Punjab(Punjab Agricultural University, Ludhiana, 2018) Gurpreet Singh; Jain, SandeepThree simultaneously occurring syndromes viz. stem gummosis and slow vine decline; quick wilting and leaf blight were deciphered in the bottle gourd fields and their primary pathogenic causes were established. All the three types of syndromes were more prevalent in south-western districts of Punjab. The incidence of stem gummosis and slow vine decline varied from 0 to 68.30 per cent and 20.57 to 67.89 per cent, whereas the severity varied from 0 to 51.22 per cent and 11.77 to 39.33 per cent in the years 2015 and 2016 respectively. The incidence of quick wilt varied from 2.33 to 57.00 per cent and 5.15 to 27.78 per cent in the years 2015 and 2016 respectively. The incidence of leaf blight varied from 35.57 to 85.15 per cent and 28.88 to 80.15 per cent whereas the severity from 11.55 to 53.33 per cent and 20.44 to 59.67 per cent in the year 2015 and 2016, respectively. Pathogenicity tests were conducted to prove Koch’s postulates and identification of organisms was done through morphological as well as molecular studies. The causal organism of stem gummosis and slow vine decline was identified as Fusarium verticillioides (Sacc.) Nirenberg. The pathogen associated with quick wilting was identified as Fusarium oxysporum Schltdl. and the pathogen associated with leaf blight was identified as Lasiodiplodia theobromae (Pat.) Griffon & Maubl. Best medium for vegetative growth of F. verticillioides was observed to be potato dextrose agar followed by czapek’s dox agar and richard’s agar while for F. oxysporium it was czapek’s dox agar followed by potato dextrose agar and richard’s agar and for L. theobromae it was observed to be potato dextrose agar followed by V8 juice agar and rye agar. None of the test genotypes showed the resistant or moderately resistant reaction against stem gummosis and slow vine decline or quick wilting whereas two bottle gourd genotypes were adjudged as the moderately resistant against leaf blight. Under in vitro evaluation of fungitoxicants, carbendazim 50 WP was found to be the most effective fungicide against Fusarium verticillioides and Fusarium oxysporum. Trifloxystrobin + tebuconazole 75% WG was found to be the most effective fungicide against Lasiodiplodia theobromae. Soil drench with carbendazim 50 WP @ 0.2 per cent along with foliar application of tebuconazole 25 EC @ 0.1 per cent three times at fortnightly interval starting from end of July proved to be the most effective against stem gummosis and slow vine decline. Against leaf blight, three foliar sprays of propiconazole 25 EC @ 0.1 % were found to be most effective against leaf blight of bottle gourd under field conditions. This is the first systematic study on stem gummosis in Punjab.ThesisItem Open Access Pathotyping of Pyricularia oryzae causing neck blast of basmati rice in Punjab(Punjab Agricultural University, Ludhiana, 2018) Jasvir Singh; Jain, JyotiThe neck blast disease was prevalent throughout the Punjab state with disease intensity ranging from 5 to 65 per cent on different basmati varieties. The highest disease incidence was observed in south western districts of the state on variety Pusa basmati 1401 followed by the Pusa basmati 1121, Pusa basmati 1509, CSR 30 and PB 3 respectively. The neck blast isolates of Pyricularia oryzae were significantly variable from each other with respect to colony colour, colony texture, colony form, colony margin, mean radial growth (mm), spore size and sporulation intensity. Eighteen isolates were designated as medium growers with Kr value of 6-8mm/24 hours and only three isolates (NB-1, NB-4 and NB-33) as fast growers having Kr > 8mm/24 hours. All the isolates cultured on oatmeal agar medium (OMA) produced higher conidia per ml (7.49×106) than on paspalum grass medium (6.74×106). Seventeen isolates were pathotypically characterized based on different components of aggressiveness viz. area under disease progress curve (AUDPC), lesion length, incubation period (IP 50), disease incidence (%) and sporulation intensity using near isogenic lines (NILs). Hierarchical cluster analysis of these aggressiveness components categorized the isolates into three distinct groups. Isolate NB-7 was found to be the most virulent followed by NB-51whereas isolate NB-6 was the least virulent. None of the single blast resistance gene was effective against different isolates of neck blast. Out of 69 genotypes evaluated, none was found to be resistant against neck blast disease. Only 4 entries viz. Tetep, Pusa basmati 1637, INGR 15001 and INGR 15002 showed moderately resistant reaction to most virulent isolate NB-7 and can be used as donors in neck blast resistance breeding programme. This is the first systematic study on pathotyping of neck blast isolates in Punjab suggesting the occurrence of three distinct pathotypes in the state.ThesisItem Open Access MANAGEMENT OF ASCOCHYTA BLIGHT (Ascochyta rabiei (Pass.) Labr.) OF CHICKPEA(Punjab Agricultural University, Ludhiana, 2018) Mohammdy, Wazir Ahmad Dost; Upasana RaniThe present investigations on “MANAGEMENT OF ASCOCHYTA BLIGHT (Ascochyta rabiei (Pass.) Labr.) OF CHICKPEA” have been carried out at the Pulses Section and Experimental Area, Department of Plant Breeding and Genetics, Punjab Agricultural University, Ludhiana during rabi 2016-17. Six chickpea cultivars were grown on five different dates to observe the development of Ascochyta blight during rabi 2016-17. The disease score on D2 (25th October) and D3 (5th November) were statistically at par and these dates can recommended for sowing chickpea for getting good yields by lowering the blight. The most congenial date for development of blight was from 15th to 25th November and BG 1053 was the most susceptible variety. The period (SMW 6-14) showed consistent correlations of disease score with temperature, rainfall number of rainy days and wind speed. One hundred and fifty germplasm and inter specific derivative lines were evaluated under artificial epiphytotic conditions. Four germplasm lines viz. FLIP 09-153 C, FLIP 09-98C, FLIP 09-192 C, FLIP 09-218C and two interspecific derivative lines viz., ICL 8777, ILC 8730 were found to be highly resistant with disease score of 1.0. Nine fungitoxicants with different concentration were evaluated for their efficacy against Ascochyta rabiei under in vitro conditions. All the systemic fungitoxicants were found effective against Ascochyta rabiei and gave complete inhibition of fungal growth at 75 ppm. Maximum mean per cent growth inhibition was found in difenconazole 25 EC (93.13). All the systemic fungitoxicants were found to be highly effective with ED50 of < 1 ppm. The fungitoxicants were also sprayed in the field both at PAU, Ludhiana and Gurdaspur and all systemic fungitoxicants effectively managed Ascochyta blight. Score was found to be effective at 0.1 and 0.05% with per cent disease intensity of 12.04 and 12.41 per cent at Ludhiana and 11.48 and 12.96 per cent at Gurdaspur giving maximum disease control compared to control (59.82 and 62.96 per cent). The next best fungitoxicants were Contaf (0.2 and 0.1%) followed by folicur (0.1 and 0.05%) and Tilt (0.1%) The yield in terms of 100-seed weight (g) and yield (q/ha) improved in all the treatments sprayed with systemic fungitoxicants as compared to control.ThesisItem Open Access Characterization of Begomovirus(es) causing yellow mosaic disease (YMD) in mungbean(2018) Navkiran Kaur; Sirari, AsmitaBegomovirus(es) causing yellow mosaic disease (YMD) on pulses during summer and kharif season in Punjab were characterized. Ninety YMD infected samples collected from different cultivated varieties, germplasm and advanced breeding lines grown at different locations were subjected to PCR amplification with two legume yellow mosaic viruses (LYMV) species specific primers. Both two species i.e. Mungbean yellow mosaic virus (MYMV) and Mungbean yellow mosaic India virus (MYMIV) were detected from all the samples. Out of ninety, DNA A and DNA B component of twenty three samples were sequenced and subjected to BLASTn. Mungbean yellow mosaic virus [Urdbean: New Delhi: 2011] accession no JQ398669.1 was prevalent in both summer and kharif season. It was observed that DNA B component was more variable than DNA A component. Alpha satellite was not found in any of the samples. Characterization of beta satellite indicated association of Cotton leaf curl Multan beta satellite with YMD infection on summer mungbean crop whereas, Malachra yellow vein mosaic beta satellite was associated with YMD infection on kharif pulses. Similar strains of virus were also observed on Amaranthus viridis, Commelina benghalensis, Cyperus rotundus, Digitaria singuanalis weed species and on hedge species Duranta. Further, out of fourteen interspecific derivative mungbean lines namely SML 1808, SML 1827, SML 1839 and SML 1840 were found resistant to YMD.ThesisItem Restricted DETECTION AND CHARACTERIZATION OF CITRUS GREENING BACTERIUM (Candidatus Liberibacter asiaticus) IN PUNJAB(Punjab Agricultural University, Ludhiana, 2018) Shubhanka; Thind, S.K.The present study was conducted on the greening disease of citrus in the Department of Plant Pathology, PAU, Ludhiana during the year 2015-17. Surveys were conducted in the citrus growing districts- Bathinda, Fazilka, Hoshiarpur, Ludhiana and Sri Muktsar Sahib of Punjab. The incidence of the disease ranged between 5% to 60% in all the cultivars with mean incidence of 17.9%. The disease incidence was highest in Ludhiana (23.4%) and lowest in Sri Muktsar Sahib (16.2%). Interveinal chlorosis, green island and blotchy mottle of leaves and bi-coloured fruit symptoms of disease were observed during the surveillance on Kinnow mandarin, Sweet orange and Daisy cultivars of citrus. Of the three agro-climatic zones of Punjab, maximum incidence was recorded in Central zone (23.4%) as compared to Arid-irrigated (17.63%) and Sub-mountainous (16.5%). The incidence of disease was 17.34% in Kinnow, 17.24% in Sweet orange and 40% in Dasiy. The presence of greening bacterium (Ca. Las) was confirmed through PCR in 39 symptomatic Kinnow leaf samples from Fazilka, Hoshiarpur and Ludhiana. The HLB bacterium was also detected in 15 and 25 batches of adult psyllid vector (Diaphorina citri Kuwayama) through PCR indicating an association of psyllid vector with the bacterium. The isolation of Ca. Las on Liber A medium was tried but unable to culture HLB bacterium from the leaves of greening infected PCR positive Kinnow plants. The disease was characterized by sequencing of 16S rRNA from four Kinnow isolates (PLK-NO, PLK-HO, PHK-MG and PFK-KW) which showed 98% to 100% similarity with reported isolates of Candidatus Liberibacter asiaticus from Asia. All the four isolates showed 99-100% nucleotide identity.