Khanin Pathak

Genetic diversity in upland rice of Assam assessed through SSR markers

The genetic diversity in 100 upland rice germplasm of Assam, was analyzed using 120 SSR markers, of which 98 (81.66%) showed useful polymorphism with a total of 183 alleles. The number of alleles ranged from one to three with an average value of 1.867 per locus. The markers showed an average effective number of alleles to be 1.73, average Neis gene diversity was 0.393, and average Shannons Information Index was 0.556. The effective number of alleles and Shannons information index showed positive correlation with the observed number of alleles. The resolving power of the 98 SSR primers ranged from 0.72 for primer RM38 to 2.82 for primer RM592. SSR generated an average similarity of 0.460 with similarity ranging from 0.07 to 1.00. Sufficient diversity was detected among the accessions. A basic molecular database was created for upland rice genotypes, which will be useful to identify and map useful genes that are harbored by these germplasms.

Nutritional Composition of Five Soil-Dwelling Scarab Beetles (Coleoptera: Scarabaeidae) of Assam, India

Abstract Proximate and elemental compositions of five soil-dwelling scarabs, Lepidiota mansueta Burmeister, Lepidiota albistigma Burmeister, Xylotrupes gideon (Linnaeus), Catharsius molossus (Linnaeus), and Sophrops iridipennis (Brenske), were assessed. Nutrient content varied widely, and the ranges of proximate contents were as follows: moisture (2.04–2.55%), crude protein (68.54–79.33%), crude fat (4.00–5.50%), crude fibre (5.16–8.28%), total mineral (0.80–4.98%), and carbohydrate (5.28–11.84%). Caloric content was greater in L. mansueta (379.29 kcal) compared to the other four species. The caloric contents of X. gideon (375.54 kcal) and C. molossus (375.19 kcal) were at par but significantly higher than those of L. albistigma (371.04 kcal) and S. iridipennis (361.55 kcal). Sodium content ranged 23.16–35.91 mg/100 g; potassium 14.20–44.33 mg/100 g; calcium 23.33–33.37 mg/100 g; iron 1.41–37.05 mg/100 g; copper 2.01–16.13 mg/100 g; zinc 2.38–15.86 mg/100 g; and manganese 1.09–19.66 mg/100 g. The phenol, flavonoid, and antioxidant activities of L. mansueta and L. albistigma were 4.00 and 6.42 mg catechol equivalent/g, 1.59 and 3.71 mg quercetin equivalent/g, 22.60, and 28.20%(DPPH activity), respectively. Tannin content was higher in L. albistigma (13.30 mg/g) than in L. mansueta (3.24 mg/g). Based on our study, these scarab species can be explored as food supplements and nutraceutical resources in ensuring food security.

QTL Analysis in Aromatic Rice of Assam, India

The study was carried out to identify quantitative trait loci (QTLs) controlling 12 morphological traits in rice using a F2 derived from Ranjit and Kola Joha cross. A framework linkage map of 1387.9cM was developed using 102 SSR markers and other few markers linked to aroma. QTL analysis based on composite interval mapping identified 24 QTLs was for 12 traits. Among them two QTLs were identified for grain aroma each on chromosome 5 and chromosome 8, out of which the QTLs between Aro1-BAD2 is in similar position with aroma gene of Basmati rice. Most of the QTLs identified in the current study, showed a range of partial to over-dominance effects, indicating complexity of the traits under consideration. Some genomic regions were associated with more than one trait, indicating linkage and/or pleiotropic effects. Marker linked to the QTLs can be considered for use in marker assisted breeding as being confirmatory to other reports.

Variability in Mineral Content of indica Rice Genotypes of Assam, India

Significant genetic variations for grain concentration of all 9 mineral elements were observed. The range of macro elements like, phosphorous (P), sodium (Na), potassium (K), calcium (Ca) and magnesium (Mg) were recorded in the range of 0.272–0.412 per cent, 0.051–0.065 per cent, 0.190–0.232 per cent, 0.023–0.036 per cent and 0.039–0.049 per cent, respectively. The micro elements like iron (Fe), manganese (Mn), copper (Cu) and zinc (Zn) were found to be 2.34–4.21mg/100g, 1.02–3.87 mg/100g, 0.400–1.64 mg/100g and 2.10–4.66 mg/100g respectively. On average, the nine mineral content in rice genotypes were followed an order as P>K>Na>Mg>Ca>Zn>Fe>Mn>Cu. There is a significant correlation observed among different minerals. Highest estimate of GCV and PCV was recorded for Cu, which indicate plentiful variability of Cu content for genetic improvement. High heritability coupled with high genetic advance were observed for Cu, Mn, Zn and Fe which indicate preponderance of additive genetic effect in control of these minerals, which suggested the scope of genetic improvement of these minerals based on phenotypic performance.

Variability in Grain Quality Characters of Local Winter (Sali) Rice of Assam, India

The study on rice germplasm showed considerable genetic variation in different quality characters analyzed. The grain length varied from 5.10 to 8.03 mm, grain width from 2.00 to 3.17 mm, cooked grain length from 7.40 to 12.37 mm, cooked grain width from 3.30 to 7.17 mm, grain elongation ratio from 1.29 to 2.02 and grain widening ratio from 1.37 to 3.32. On dry weight basis, moisture contents of genotypes ranged from 8.33 to 10.74 per cent, amylose from 0.05 to 29.6 per cent, starch from 70.37 to 82.83 per cent, GC from 53 to 100.03 mm, GT from 2 to 7, crude fat content from 2.64 to 3.76 per cent, crude protein content 8.10 to 10.32 and lysine content from 2.71 to 3.39 (g/100 g of protein). UPGMA based cluster analysis revealed the existence of two major clusters (A and B) with additional sub clusters within each major cluster in indica rice genotypes under study for grain quality data. The difference between GCV and PCV was less for all characters except GT, which indicate greater correspondence between phenotype and genotype and less environmental influence and greater role of genetic factors on expression of grain quality traits. Based on above results amylose content trait would be highly effective to be used in breeding programmes for improving cooking and eating quality.

Microsatellite based association studies for grain mineral content in local winter (Sali) rice of Assam

In present investigation, grains of one hundred indica rice genotypes were analyzed for nine mineral contents namely, phosphorus (P), potassium (K), sodium (Na), magnesium (Mg), calcium (Ca), zinc (Zn), iron (Fe), manganese (Mn) and copper (Cu) and genotyped using 112 SSR markers. STRUCTURE analysis identified k=4, indicating at least four distinct groups in a set of 100 rice accessions. Genomewide scanning detected a total of 10 significant markertrait associations (P<0.01), with the R2 values ranging from 8.85% to 24.25%. Three markers, RM231 on chromosome (Chr.) 3, RM234 (chr. 7) and RM162 (chr. 6), were found to be linked for Ca. Three SSR markers, RM3 (chr. 6), RM400 (chr. 6) and RM286 (chr. 11) were found to be associated with Cu content. RM 311 on chr. 10 was found to be associated with Fe content. P was found to be associated with three SSR markers, namely, RM536, RM234 and RM600 on chromosomes 11, 7 and 1, respectively. Some novel QTLs were also detected and implications of these results are discussed.

Assessment of Genetic Diversity of Indigenous Glutinous Rice Genotypes of Assam using SSR Marker

Rice is considered as the best staple food among all cereals. In the present investigation, sixty five polymorphic SSR primers generated a total of 354 alleles. The number of alleles detected by a primer ranged from 2 (RM 105 and RM 171) to 9 (RM 311) with an average of 4.75 alleles per locus. The highest PIC (0.995) was recorded in RM 206 of chromosome 6 and the lowest PIC (0.613) was recorded in RM 171 of chromosome 2. SSR generated an average similarity of 0.294 which ranged from 0.061 (between ‘Lothow Bora and Kmj Bora74) to 0.790 (between ‘Poita Bora 2 and Pakhiloga Bora). Cophenetic correlation studies revealed that SSR data had a good fit (r = 0.81170). The dendrogram classified the rice germplasm under study into two main clusters with around 19 per cent similarity. In spite of the high variability, SSR markers used could not produce unique alleles for the genotypes studied. Incorporation of more germplasm, analysis for their nutritional parameters along with good agronomic traits and use of more SSR markers would help to find suitable germplasm for the rice breeding programme.

Changes of Rain Water Balance in Jorhat District of Assam, India

The surface water and groundwater resources of a region play a major role in agriculture, livestock production, industrial activities, forestry and fisheries. In this work, monthly, seasonal and annual trends of rainfall balance have been studied using monthly data series of 36 years (1975–2011). The analysis revealed that except for May, rainfall balance decreased in all the months as indicated by Man-Kendall rank statistics. The results of the linear trend lines for the period of study clearly demonstrated a general tendency for a decrease in monsoon rainfall balance in the area. Mann-Kendall test also showed a decreasing monsoon rainfall balance at 6% probability level. Pre-monsoon balance showed non-significant increase (72% probability level) while post monsoon balance showsed non-significant decrease (75% probability level). Overall annual balance decreased at 27% probability level.