Assessment of Various Variability Parameters and Correlation of Quantitative Characters in Maize (Zea mays L.) Inbred Lines

The present research problem was carried out to assess the variability parameters, heritability, genetic advance and correlations among various quantitative traits in maize inbred lines. A total of 69 inbred lines were evaluated in alpha lattice design with 2 replications at Winter Nursery Centre, Hyderabad. ANOVA results displays genotypes were significantly different from each other. From the results it was depicted that Phenotypic Coefficient of Variation (PCV) was higher than Genotypic Coefficient of Variation (GCV) indicating the influence of environment. The traits, No. of kernels per row, Cob weight, Grain yield per cob showed high GCV and PCV values likewise Days to 50% tasseling, Days to 50% silking and Days to 75% dry husk showed low GCV and PCV values. Most of the characters showed high heritability and traits such as Plant height, Tassel length, Ear length, No. of kernels per row, Cob weight and Grain yield per cob showed high GAM and its values ranged from 21.5% to 101.30%. So, the traits such as No. of kernels per row, Cob weight and Grain yield per cob can be used for further crop improvement in the breeding programme. Of all the traits under study except, Days to 50% tasseling, Days to 50% silking and Days to 75% dry husk showed positive significant correlation with grain yield per cob indicating selection for the traits will enhance the grain yield whereas the excepted traits showed negative significant association with grain yield per cob indicating selection for these traits is also essential as it reduces duration of crop.

Isolation and Characterization of Bacterial Endophytes from Maize Genotypes Varying in Resistance against Macrophomina phaseolina

The present work aims to isolate and characterize the bacterial endophytes associated with different maize genotypes varying in resistance to disease reaction against Macrophomina phaseolina. A total of 50 endophytic bacteria were isolated from root and stem of healthy maize plants at 30 DAS, 60 DAS by using two different media like TSA, NA medium and maximum number of endophytic bacterial population were recovered from root followed by stem in all the genotypes and TSA medium was found to be the most suitable medium for deciphering maximum endophytic bacterial diversity. The isolated bacterial endophytes were characterized on the basis of morphological parameters viz., size, shape, colour, margin and texture, elevation, gram staining reaction and it was observed that Gram positive bacteria (68.0 %) formed the dominant group. The colony characterization revealed that circular forms (38.0 %) were dominated. Among the colony features the colonies with entire margins (66.0 %) and convex elevation (44.0 %) were found to be dominating.

Combining Ability Analysis for Grain Yield and Yield Attributing Traits in Maize

Combining ability of inbred lines is the ultimate factor determining future usefulness of the lines for hybrid development while, an idea about the nature of gene action controlling the yield and yield contributing characters is important for development of fruitful breeding programme. Owing to this, the present study was carried out to investigate the General Combining Ability (GCA) and Specific Combining Ability (SCA) effect of parental lines and hybrids respectively, and to deduce the type of gene action regulating the grain yield and its components. The 30 single cross hybrids were generated by crossing 6 lines with 5 testers in line x tester mating system and evaluated along with four checks at three locations for the estimation of combining ability effects. Significant differences were observed among the inbred lines, testers, hybrids and parents vs. hybrids for most of the studied traits. The non-additive gene action was predominant for all studied traits except plant height. PFSR 145 found to be good general combiner for traits such days to 50% tasselling, days to 50% silking, days to maturity, plant height and ear height. GP 329 is best general combiner for ear girth, number of kernel per ear, number of kernels per row, 100 kernel weight and grain yield. These parents could be used in future breeding programme for the accumulation of favourable genes and thereby improve maize yield with desirable traits. Hybrid GP 82×GP 83 found to be the best specific combiner for days to 50% tasseling, days to 50% silking, days to maturity, number of kernels per ear and grain yield. The hybrid GP 82×GP 83 can be further tested extensively for the development of potential early maturing hybrids.

Screening of Tropical Maize Inbred Lines by Artificial Infestation for Resistance against Invasive Fall Armyworm in India

Aim: This study was aimed to find resistance sources against FAW. Study Design: Randomised Block Design. Place and Duration of Study: The Present study was conducted at Maize Research Centre, Hyderabad with promising germplasm during Kharif-2021, Rabi-2021-22 and Kharif-2022. Methodology: Field-collected FAW egg masses were reared using maize leaf- and stalk-based diet at 27 ± 1 °C, 60 ± 5% relative humidity and 12 h day length. The resulting neonates were used to infest the seedlings of 34 diverse tropical maize inbred genotypes. Results: A total of 15 genotypes were found to have recorded a leaf damage score of less than 5 with the least score recorded in BML 2 (3.24), followed by BML 11 (3.34), BML 7(3.37), BML 5 (3.37), BML 8 (3.49), CM 201 (3.60), BML 32-2 (3.91), CM 132 (3.97), BML 10 (4.01), BML 6 (4.02), BML 13 (4.34), CM202 (4.34), CM 131 (4.68), BML 90 (4.82), BML 45 (4.95) and displayed moderate resistance. Conclusion: Out of 34 inbred lines studied 15 were found to be moderately resistant to fall armyworm based on LIR and cob damage score under artificial infestation.

Telangana Jonna 1(CSV 41): A High Yielding, Dual Purpose, Potential Sorghum Variety

Aims: The aim of this study was popularize the developed high yielding, dual purpose, potential sorghum variety and its acceptability by the farming community.Study of Design: Randomized Block Design.Place and Duration of Study: The Present study was conducted at Regional Agricultural Research Station, Palem, Nagarkurnool and evaluated across fifteen AICRP centers at national level from 2010 to 2019.Methodology: A high yielding, dual purpose sorghum variety was derived from a cross between SPV-86 x ICSR-89064 through Pedigree method of breeding and subsequently it was evaluated at station level from 2013 – 2015 and also at AICRP system from fifteen centers during 2016 – 2018 for its grain and fodder yield and resistance to pests and diseases and showed superior performance over the three nation checks.Results: Sorghum culture SPV 2437 recorded highest grain and fodder yield of 3179.8 kg ha-1 and15900.2 kg ha-1and yielded +39.25%, +3.86% and +14.88% higher grain yield and +92.48, +13.59, and +8.46 higher fodder yield superiority than checks CSV 17, CSV 20 and CSV-27 and shown 3.67 mean field grade and 4.37 mean threshed grade showing resistant reaction to grain mold disease.Conclusion: The sorghum variety SPV 2437 with higher grain and fodder yield, resistance to pest and disease and good cooking quality as compared to the check varieties was released through central varietal release committee during 2020 for Zone I (Andhra Pradesh, Telangana, Tamil Nadu, Rajasthan and Gujarat states) on the name of Telangana Jonna 1/CSV 41 and gaining its importance across the states for its high potential yield.

Concentration of radon, thoron and their progeny levels in different types of floorings, walls, rooms and building materials

Radon, thoron and their progenies are the most important contributions to human exposure from natural sources. Radon exists in soil gas, building materials, Indoor atmosphere etc. Among all the natural sources of radiation dose to human beings, inhalation of radon contributes a lot. The work presented here emphasizes the long term measurements of radon, thoron and their progeny concentrations in about 100 dwellings using solid state nuclear track detectors. Measurements were made using dosimeters and the concentrations were estimated by knowing the track density of films through spark counter, and sensitivity factor for bare, filter and membrane films. Presence of radon and thoron in houses is the effect of several aspects such as the activity concentrations of uranium, radium and thorium in the local soil, building materials, ventilation of houses and also entry of radon into houses through the cracks in floor/wall. The observations reveal that the concentrations of radon and/or thoron are relatively higher in granite than in concrete, cement and bricks. In continuation to this the concentration observed in bathrooms is more compared to kitchen, bedroom and living rooms. This study discloses that the residential rooms of good ventilation will avoid the health hazards due to radon and its rich materials