The research work on variability and genetic diversity was conducted in thirty-two landraces of aromatic rice from various states of north eastern along with two national variety PD-1503 and Basmati 370 in the experimental field of Genetics and Plant Breeding, College of Agriculture, CAU, Imphal, during Kharif, 2021. Agro-morphological characters showed significant variations, starch content and crude protein content were non-significant. Phenotypic variance was higher than the corresponding genotypic variance. High genotypic and phenotypic coefficient of variation was observed for the characters such as grain yield per plant, number of grains per panicle, number of panicles per plant and length of leaf blade. Among quality parameters, crude fat content and crude protein content exhibit high genotypic and phenotypic coefficient of variation. High heritability coupled with high genetic advance was observed in number of panicles per plant, number of grains per panicle and crude fat content. The genotypes were grouped into four clusters following Tocher’s method of clustering. Maximum genotypes viz., 27 genotypes fall in cluster I, while four genotypes fall in cluster II, cluster III has 2 genotypes whereas cluster IV has solitary genotype. Significant amount of variability and genetic diversity observed in the present investigation could be helpful in further improvement of the reported superior genotypes or selection of parents for further hybridization program.

Northeastern India has a diverse genetic reservoir of rice that remains largely underutilized for improving crop resilience against biotic and abiotic stresses. One of the most devastating threats to rice production worldwide is rice blast disease, caused by the fungus Magnaporthe oryzae. Despite this, the resistance genes present in local rice landraces have not been thoroughly explored. This study investigates the distribution of major blast resistance genes in rice germplasm from Northeastern India. A total of 58 genotypes from the region were screened, alongside one susceptible genotype (HR-12) and one resistant check (Tetep), in a uniform blast nursery to assess their responses to the disease. Fourteen gene-specific markers were employed to identify the presence of blast resistance genes. The results revealed that the blast resistance gene Pik-p was the most widely distributed, followed by Piz (96.66

A survey was conducted on aromatic rice during the kharif seasons of 2019 and 2020 in the five valley districts of Kakching, Thoubal, Bishnupur, Imphal-East, and Imphal-West, Manipur to assess the natural disease occurrence of blast, brown spot and sheath blight diseases. The survey revealed that disease incidence and severity varied with locations. Blast, brown spot, and sheath blight have an overall disease incidence of 36.94

Confirmation of true F1 hybridity in Indian Mustard is a crucial step in the selection of positive segregating individuals after the hybridization program in crop breeding. The use of molecular markers is the most reliable and rapid method rather than the grow-out test (GOT). The present study aimed at the assessment of genetic purity of the generated F1 plants in Indian Mustard (Brassica juncea) using molecular markers as well as visual disease reaction as PDI. Out of 80 SSR markers used for the parental polymorphism study, 18 were found to be polymorphic between the parents Varuna and CAULC-2 (Locally collected from Kakching wairi, Manipur and highly tolerant o Albugo candida). Among polymorphic markers obtained from two parental line, the markers At2g36360 could identify the true F1 plants. The plants that showed lower PDI were selected for further development of segregating or mapping population. This study showed that these SSR markers may be used as referral SSR markers for testing hybridity and genetic purity in Brassica breeding programs.

The present study was carried out at Central Agricultural University Research Farm, Andro, Imphal East, Manipur, during kharif 2021 to estimate genetic variability parameters of thirty three vegetable soybean genotypes for ten characters. Statistical analysis showed significant differences between the tested genotypes. Maximum phenotypic coefficient of variation value (66.54) and genotypic coefficient of variation value (66.53) was recorded for character fresh pod yield/plant. Heritability (in broad sense) value ranged from 99.99 to 86.53. The estimates of genetic advance expressed as percentage ranged from 137.24 to 118.09. Highest GA over its mean was recorded for fresh pod yield/plant (137.24), followed by number of pods/plant (118.09). The correlation study showed a positive and significant correlation between fresh pod yield/plant and the number of pods/plant, 100 fresh pod weight and 100 fresh seed weight.

Ten cultural media, namely Potato sucrose agar (PSA) medium, Potato dextrose agar (PDA) medium, Czapek’s dox agar medium, Corn starch agar medium, Oat meal agar (OMA) medium, Rice straw agar medium, Rice grain agar medium, Rice leaf extract agar medium, Malt extract agar medium, and V8 juice agar medium, were used to observe the growth of three fungal pathogens of aromatic rice, viz., Pyricularia oryzae, Bipolaris oryzae, and Rhizoctonia solani. The radial growth and colony characteristics were greatly influenced by the medium used. In a comparative study of the higher mycelial growth of the three test fungi at ten different mediums, the best performance was observed in rice straw medium (Pyricularia oryzae and Bipolaris oryzae) and in rice leaf agar medium (Rhizoctonia solani). These results will find use in further fungal taxonomic in vitro studies.

Access to a diverse range of genetic material is quite important for the success of any plant breeding effort.An evaluation was commenced to determine genetic diversification of 30 genotypes of rice based on 14 seedling traits by employing multivariate analyses i.e., hierarchical cluster and Principal Component Analyses (PCA).Cluster analysis segregated the genotypes into five classes which are in contrast for germination, seedling length, root length, seedling vigour Index-I and seedling vigour index-II.The first three PCs explained 89.07% of the total variability were the major traits in discriminating the genotypes.In grouping of genotypes, the hierarchical cluster and PC analyses was used.Parental combinations from the five clusters with higher value of Euclidean distance could be used for genetic improvement.Generally, is the most diverged genotype from others.Thus, crossing of this genotype with Ashangbrokakara, Moliro, Stejari, and Kawnlang might result in heterotic expression in the F 1 and substantial variability in the successive segregating population.

A study was undertaken to evaluate the genetic parameters and correlation between the root and shoot traits in 50 upland rice genotypes of Manipur along with 3 checks for drought tolerance. The highest GCV and PCV values were recorded in Root fresh weight with 42% and 41.9% in controlled and 34% and 33.7% in stressed conditions. This was followed by Root dry weight (35.29% & 34.79% and 25.2% & 23.97%) in controlled and stressed conditions, respectively. The estimates of heritability were observed to be high in magnitude for all the characters. Heritability ranged from 80.32 per cent (number of tillers) and 99.7 per cent (root fresh weight) in controlled and 92.36 per cent (number of tillers) and 99.36 (shoot length) in stressed conditions. Correlation reveals highly positive and significant association at 0.01% in both controlled and stressed conditions. The large genetic variation found in this population can be exploited further to develop a few forward breeding high-yielding lines with better drought tolerance ability and used as drought donors in drought breeding programs.

White rot of onion caused by Sclerotium rolfsii has devastated onion cultivations at various small scale onion growing locations in Manipur. The maximum white rot disease incidence was observed during the month of April in all the onion species and the minimum disease incidence was observed during February month. The disease symptoms were not apparent during the first three months after planting. The symptoms of white rot became evident during second week of February with yellowing of leaves starting from tips and gradually progressing downwards. The disease became most obvious during last week of March to first week of April when the basal part of onion stem starts rotting and drooping and the plant wilts and collapse. The bulbs of infected plants are decayed and accompanied by the signs of the pathogen including white mycelium and sclerotia.

The present investigation was carried out to identify the potential donors of resistant gene(s)/the source of white rust disease in B. juncea using 30 genotypes, including locally adapted accessions and advanced breeding lines. Out of 30 genotypes, ten lines viz. Bio-YSR, CAULC-1, CAULC-2, CAULC-3, CAULC-4, CAURM-2, CAULR-7, CAURM-4, CAURM 4-1, and CAURM 4-2 exhibited a lower PDI value (lesser than mean 10.83) with a superior agronomic performance related with the disease. The evaluation of these ten genotypes for the presence of the BjuWRR1 gene using a gene-based marker depicted the presence of the functional allele of the BjuWRR1 gene in the five genotypes viz., Bio-YSR, CAULC-1, CAULC-3, CAURM 4-1 and CAURM 4-2. When compared with the sequenced amplicon of these genotypes, it is found to be identical with that of an east European Brassica juncea line, Donskaja-IV, the completely resistant genotype against various isolates of Albugo candida. The findings from the present study suggested that besides Bio-YSR, the local lines of Manipur CAULC-1 (Local Yella of Potshangbam) and CAULC-3 (Local Yella of Kakching Lamjao) can be used as the potential white rust resistance sources/donors in disease resistance breeding programmes for the development of elite B. juncea cultivars in the future. In addition to the local lines, two improved advanced lines, viz. CAURM 4-1 and CAURM 4-2, obtained from a hybridization programme, may be further evaluated for releasing resistant varieties against white rust.

Using Mahalanobis D2statistics, the level of genetic diversity among soybean genotypes based on 12 agro-morphological traits was investigated in this study. A total of 100 soybean genotypes were grouped into six clusters. Cluster I had the maximum number of genotypes (53 genotypes), followed by cluster II (37 genotypes), cluster III (6 genotypes), clusters IV and V (1 genotype each), cluster VI (2 genotypes). Clusters I and VI had the greatest inter-cluster distance (117618.10). Intra-cluster distance ranged between 0.00 and 9830.83. The biggest contribution to total divergence came from character plot yield (25.0 %). Cluster VI had the highest cluster mean values for yield and its component traits. Based on inter-cluster distance, cluster mean values, and mean per se performance, it is recommended to utilize genotypes of cluster I and cluster VI, I and III, III and IV, II and VI, respectively, for future hybridization programs to develop high yielding genotypes. Keywords: soybean, clusters, genetic diversity

This study was carried out in Andro Research Farm, CAU, Imphal to study diallel analysis of yield and its important components in 10 genotype of wheat during two consecutive rabi season 2017-2019. All the 10 genotype and their 45 F1’s cross combination exhibited significant difference in characters under study Combining ability analysis showed that both gca and sca variances value were highly significant for most of traits studied in F1 progenies which suggest importance of both additive as well as non-additive genetic components for the expression of characters under study. VL 3017 was found good general combiner for the characters like fifty percent flowering, days to eighty percent maturity, plant height, total number of tillers per hill, total number of spikelets per spike, spike length, total number of filled grains per spike and grain yield per plant. Among all 45 crosses, cross combination VL 3018 x HS 490 and VL 892 x UP 3017 were good specific combiners for the grain yield per plant character in F1 generation.

Under the Farmer FIRST Programme, Central Agricultural University, Imphal has identifiedtwo villages viz., Yairipok Top Chingtha and Yairipok Yambem of Imphal East district, ofManipur covering, a total of 600 farm families. However, farmers are well aware of cultivatingmajor Kharif and Rabi cereals, pulses, oilseeds and other major vegetables like cabbage, tomato,cauliflower, etc. The farming community, in general are marginal and small farmers. The 600farm families under FFP, CAU, Imphal were categorized as marginal - 593, Small- 4, Semi-Medium- 2, Medium- 1 and Large - 0 according to their size of land holding.

Selection is effective only when the observed variability in the population is heritable in nature. Heritabilityestimates give a measure of transmission of characters from one generation to the other, as consistency in theperformance of the selection depends on the heritable portion of the variability. Thirty advanced lines of soybean were evaluated in a randomized block design with three replications to estimate heritability and genetic advance for 11 agromorphological characters under rainfed conditions during kharif 2018. High heritability accompanied with high genetic advance expressed as percent of mean was recorded in seed yield/plant, harvest index, biological yield/plant, 100 seed weight, days to 50% flowering, days to maturity, plant height and oil content, which indicates the preponderance of additive gene effects and therefore these characters possess high selective value. Thus, selection for these characters can be done for their improvement.

An experiment was conducted in research fields of the department of Genetics and Plant Breeding, College of Agriculture, CAU, Imphal to study the nature and degree of association between yield and its component characters and their direct and indirect effects on grain yield in aromatic rice genotypes of North east region of India. Among the important characters studied no. of grains per plant, no. of panicles per plant, 1000 grains weight, panicle length and plant height showed high significant positive correlation with grain yield per plant. Maximum direct effect on grain yield was also observed from no. of grains yield per plant followed by no. of panicles per plant, panicle length, plant height and 1000 grains weight.

The present study was conducted to evaluate the plant nutrient traits in 12 baby corn genotypes by using Principal component analysis and cluster analysis during rabi 2017. Analysis of variance depicted the genotypes differed significantly among themselves for all the traits except sugar content. Variability studies revealed that PCV was observed maximum for all the traits. Maximum GCV and PCV were recorded for yield without husk followed by iron content and sugar content. Medium heritability was observed for all the traits except sugar content. Calcium content and iron content was recorded for highest genetic advance. Principal component analysis revealed that the first three principal components together accounted for 87.49 % of variability. The principal components (PC1, PC2) were highly positively influenced by sugar and iron contents, respectively. PC3 was negatively influenced by yield without husk. The 12 genotypes were grouped into three distinct clusters. The cluster-I were the largest cluster comprising of five genotypes and followed by Cluster-II (4 genotypes) and cluster-III (3 genotypes). The genotypes in cluster-I has higher iron content and yield without husk, while the genotypes in cluster-II having higher potassium, phosphorous and calcium contents. The genotypes in cluster-III exhibiting higher means for sugar and phosphorous contents.

To measure the extent of genetic variability, an experiment was conducted among twenty hybrids of quality protein maize and two open pollinated local germplasms in RBD with three replications over two seasons viz., kharif 2017 and pre-kharif 2018. The ANOVA revealed high significant differences among all the genotypes studied for all the characters except shelling percentage. The pooled ANOVA also indicated significant differences among the genotypes as well as among the environments over the two seasons. Highest PCV and GCV were recorded in ear height followed by plant height and ear weight. Highest heritability in broad sense was recorded in grain yield per plant followed by 100 seed weight and ear weight. And genetic advance as per cent of mean was recorded highest in ear height followed by ear weight and number of kernels per ro.

Anthers from four genotype of Indian mustard, namely Local Yella (CAULC-1), JD-6, Kranti and NDRE-22) were cultured in vitro to observe their androgenic responses. Different concentrations and combinations of growth regulators were supplemented in B5 and MS medium. The range of callus induction was between 16.11 and 66.39%. The maximum rate of callus induction in terms of percentage (%) was observed in MS + 3 ml/l 2, 4-D + 1ml/l BAP (66.39). Among the Genotypes CAULC-1 (Local Yella) showed the best performance for days to callus initiation and per cent of callus induction while NDRE-22 was the poorest. Maximum per cent of shoot initiation at 30 and 45 DAI (55.55% and 59.44% respectively) was observed in MS + 4 ml/l BAP + 1 ml/l NAA. Local Yella (CAULC-1) recorded the best for shoot regeneration followed by Kranti. The media composition MS + 1 ml/l NAA + 0.5 ml/l BAP showed the minimum days (12.97) and highest per cent of root initiation (45.83%) and also maximum length of regenerated root (3.42 cm) respectively. Local Yella was found to be the best genotype which took minimum time (12.44 days). Regeneration of haploid plants was confirmed by cytological examinations of the root tips of the plantlets from the callus of anther culture. The present study can be concluded that Local Yella (CAULC-1) showed better androgenic response than other genotypes under study.

Experiment was conducted during 2016-2017 on twenty cultivars/genotypes of rapeseed and mustard to understand the molecular variability using RAPD and its reaction against Albugo candida. Artificial inoculation was done by sporangial suspension and the overall average disease incidence ranged from 4.16-23.42 per cent among the tested genotypes/cultivars. RAPD analysis on twenty cultivars/genotypes of rapeseed and mustard with OPB-01, OPB-08 and OPD-13 primers revealed that OPB-01 had the highest polymorphic information content. At a distance coefficient of 0.25, twenty cultivars/genotypes were cluster into 2 major clusters, the first major cluster consists of 19 cultivars/genotypes and second major cluster consist of only 1 cultivar/genotype. Using 3 RAPD primers, all the 20 cultivars/genotypes were successfully classified except 4 cultivars/genotypes.

The experiment was carried out to study the extent of genetic diversity among the 75 genotypes of soybean [Glycine max (L.) Merr.] under rainfed condition of Manipur by employing Mahalanobis D² analysis based on 13 morphological characters. The 75 genotypes of soybean were grouped into 9 clusters. Maximum numbers of genotypes were included in the cluster I comprising 28 genotypes followed by cluster II with 13 genotypes, cluster IV with 12 genotypes, cluster III and cluster V with 9 genotypes each and clusters VI, VII, VIII and IX with 1 genotype each. The value of intra-cluster distances ranged from 0.00 to 1181. The highest inter cluster distance (8937) was observed between cluster III and IX. The character plant height (34.13%) contributed highest to the total divergence of the genotypes, followed by pods/plant (29.62%) and days to 80% maturity (14.59%). The highest cluster means values for yield and its component characters were observed in cluster IX. On the basis of inter-cluster distance, cluster mean values, mean per se performance it is advisable to attempt crosses between genotypes from cluster III and cluster IX which may lead to obtaining higher heterotic effect and broad spectrum variability in the segregants.