Morphological and Biochemical Bases of Resistance of Some Groundnut Germplasms against Tobacco Caterpillar, Spodoptera litura (Fabricius) and Leaf Miner, Aproaerema modicella (Deventer)

A screening experiment of forty germplasm lines was conducted at College Farm, College of Agriculture, Rajendranagar, Hyderabad in rabi, 2019-20 and was laid in Randomized block design (RBD) having two replicates. Three germplasm lines viz., ICGV 16679 (13.71% leaf damage), ICGV 07222 (14.00% leaf damage) and ICGV 93468 (14.25% leaf damage) showed greater resistance than the resistant check, ICGV 86031 (15.04% leaf damage) against tobacco caterpillar and with respect to resistance against leaf miner, no germplasm line was found to be superior than the resistant check, ICGV 86031 (7.82% leaf damage). However, the germplasm line, ICGV 02266 (8.35% leaf damage) was next best to the resistant check. The various morphological and biochemical characters were recorded and correlated with insect pest damage and incidence to know their role in imparting resistance/susceptibility. Resistance to various insect pests in germplasm lines was due to significantly higher trichome density on leaf lamina, higher phenol and tannin content.

Breeding Potential of Maize Germplasm Line GEMS-0067 for High Amylose Proportion

Maize varieties with high amylose proportion are more valuable for starch industry. The SBEⅡb gene encodes one of the starch branching isozymes (SBEⅠ, SBEⅡa, and SBEⅡb). Its recessive mutant amylose-extender (ae/sbe2b) decreases the total activities of SBEs and increases amylose proportion up to 60%. Here, the breeding potential of introduced germplasm line GEMS-0067 was evaluated by genotyping and phenotyping. The deletion of the ninth exon of the SBEⅡb gene, high amylose proportion, and the typical irregular granules suggested that this germplasm line was derived from the same resource of high amylose line AE11. The gelatinization and thermal properties, and degree of polymerization of starch chain showed its advantages used for high amylose breeding. However, the negative correlation between amylose proportion and starch content, as well as ker-nel filling characteristics should be overcome during breeding process.

Linkage Mapping for Foliar Necrosis of Soybean Sudden Death Syndrome

Sudden death syndrome (SDS) foliar symptoms consist of foliar chlorosis, foliar necrosis, leaf marginal curling, and premature defoliation, but resistance screening has been evaluated mostly based on the overall SDS foliar severity rather than on a specific foliar symptom. This study generated an F2 population derived from crossing the susceptible variety Sloan and the resistant germplasm line PI 243518, which exhibits resistance to both foliar chlorosis and necrosis. A total of 400 F2 lines were evaluated for foliar chlorosis, foliar necrosis, and overall SDS foliar symptoms, separately. Genotyping-by-sequencing was applied to obtain single nucleotide polymorphisms (SNPs) in the F2 population, and linkage mapping using 135 F2 lines with 969 high-quality SNPs identified a locus on chromosome 13 for foliar necrosis and SDS foliar symptoms. The locus partially overlaps with loci previously reported for SDS on chromosome 13, which is the third time the region from 15.98 to 21.00 Mbp has been reproduced independently and therefore qualifies this locus for a new nomenclature proposed as Rfv13-02. In summary, this study generated a new biparental population that enables not only the discovery of a locus for foliar necrosis and SDS foliar symptoms on chromosome 13 but also the potential for advanced exploration of SDS foliar resistance derived from the germplasm line PI 243518.

Morphological characteristics basis of resistance in Linseed (Linum usitatissimum L.) for bud fly (Dasyneura lini Barnes) in Central Uttar Pradesh

A field experiment conducted for screened 288 elite gen pool of linseed against bud fly infestation at Kanpur, India during rabi 2011-12 and 2012-13. The flowering duration showed significant positive relationship (r=0.9278 and 0.9368) with bud infestation. The maximum flowering duration 32.80 and 31.44 days was recorded on variety A-44 with highest bud infestation of 62.29 and 69.99 percent during respective years against variety C-C-1-2 which had a shortest flowering duration of 8.80 and 12.94 days with the minimum 16.38 and 14.30 percent bud fly infestation. The sepal thickness negative highly significant relationship (r=--0.7224) with bud infestation. The resistant germplasm line maximum sepal thickness (0.49 mm) had relative minimum bud infestation (6.88%) while minimum sepal thickness (0.24 mm) with maximum bud infestation(65.11%), plant height, flower colour did not show significance in bud fly resistance, whereas, flowering duration bud as well as sepal thickness showed significant impact.

Histological basis of resistance in Linseed against bud fly (Dasyneura lini Barnes) in Central Uttar Pradesh

A field experiment conducted for screened 288 germplasm of linseed against bud fly infestation at Kanpur, Uttar Pradesh during rabi season to study the historical basis of resistance of linseed against bud fly. The results indicated that the sepal thickness negative highly significant relationship (r=--0.7224) with bud infestation. The resistant germplasm line maximum sepal thickness (0.49 mm) had relative minimum bud infestation (6.88%) and was statically at par other resistant germplasm lines viz. A-95B, CI-1385, EC-1392, EC-1424, GS-234, IC-15888 and JRF-5. While minimum sepal thickness (0.24 mm) with maximum bud infestation (65.11%) which was statically at par with other susceptible lines viz. Ajgan-3-1, Ajgan-20M, Alipur (Hamirpur), Anand, GS-148, GS-440, Gunawal Local, NP (RR) 193, RAULD-7810, RLC-28 (PM), MS-14, SJKO-2, SJKO-45. The genotypes with minimum thickness of sepal suffered maximum bud infestation as compared to those with maximum sepal thickness.