Studies on Genetic Architecture Through Variability Parameters and Association Analysis in Cowpea [Vigna Unguiculata (L.) Walp.]

Genetic architecture through variability parameters and association analysis for green forage yield and its characters in 78 germplasm lines including 3 checks (MFC-8-14, UPC-5286 and TSFC-12-15) was carried out during Rabi 2015-2016. All the fifteen studied characters exhibited existence of variability significantly. This indicated existence of sufficient variability among the genotypes for the mentioned characters and sufficient scope for development of new variety or genotypes. High genetic advances as percentage of mean were recorded for green forage yield (q/ha/day). High heritability estimates were recorded for 100-seed weight (g) and by green forage yield (q/ha). Correlation coefficient showed significant positive correlation with dependent character green forage yield with green forage yield per day at genotypic and phenotypic level. Maximum positive direct effect was obtained for green forage yield per day. These results indicate that green forage yield can be improved much better way by selection. Selection for these traits is likely to accumulate more additive genes leading to further improvement of performance of genotypes. Bangladesh J. Bot. 50(3): 557-564, 2021 (September)

Genetic Evaluation and Screening of Diverse Wheat Genotypes for Spot Blotch Resistance

Production of wheat (Triticum aestivum L.) the main food source of South Asian countries including India faces several constraints including spot blotch caused by Bipolaris sorokiniana resulting in yield loss of 25–43 % depending upon the stage of infection. Fifty genotypes were evaluated for nine quantitative characters and area under disease progress curve (AUDPC) to identify superior genotype with spot blotch resistance. High heritability coupled with moderate to high genetic advance as percent of mean was registered for grains per spike, tillers per square meter, days to 50% heading and days to 50% flowering indicating the characters to be governed by additive genes. Correlation and path coefficient analysis favored days to 50% heading, days to 50% flowering and grains per spike since they had significant positive correlation with yield and simultaneous negative correlation with AUDPC and also conferring highest positive direct effect towards yield. Multiple linear regression (MLR) analysis indicated days to 50% heading to be most sensitive with negative influence on AUDPC. D2 analysis grouped the 50 genotypes into 10 clusters suggesting presence of diversity among the genotypes. Frequency distribution of AUDPC among the genotypes showed more or less normal distribution of the character. Low AUDPC score with acceptable level of yield performance were recorded for the genotypes 29882, 29610, 29473, 29940, 29477, 29748 and 30081. Identification of high yielding and less susceptible genotypes for spot blotch disease in the present investigation offered an opportunity for wheat improvement through selective breeding.

Heritabilitas Produki Telur Ayam Lokal Papua Berbeda Genotip dari Lokus 24- bp Insertion-Deletion dalam Promotor Gen Prolaktin

The heritability (h2) of a trait shows phenotypes variance of the trait caused by additive genetic variance. The h2 value is used to estimate the quantitative trait breeding value of livestock in order to improve these traits through selection. This study aims to estimate the h2 of egg production characteristics in Papua local chickens with different genotypes from the 24-bp InDel (Insertion-Deletion) locus in the prolactin gene promoter region (24-bp InDel/cPRLp locus). A total of 13 pairs of Papua local chickens consisting of 3 pairs of II genotypes (♂II x ♀II) and 11 female offspring, 5 pairs of ID genotypes (♂ID x ♂ID) and 19 female offspring, and 5 pairs of DD genotypes (DD x ♀DD) and 17 female offspring were used in this study. Observations were made on the characteristics of egg production in female offspring of each genotype group. The variance component for h2 estimation is obtained by the one-way analysis of variance method and the separation of the variance components for single pairs. The results showed that the h2 at first laying of eggs in all genotype groups was moderate (0.10 to 0.30); the h2 of the number of eggs produced from the time they first laid eggs until the age of 240 days in II and ID genotype groups was high (> 0.3), while in the DD genotype group was classified as moderate (0.10 to 0.30); and the h2 of egg weight in all genotype groups was moderate (0.10 to 0.30). The high h2 of a trait indicates that the trait is more dominated by additive genes and is more responsive to the selection treatment.

Genetic variability and character association of Bangladeshi popular varieties of mustard (Brassica rapa L.)

A study was conducted to estimate genetic variability, correlation and direct and indirect effects of yield attributes on seed yield of fourteen Bangladeshi varieties of Brassica rapa. High heritability coupled with high genetic advance was recorded in a number of secondary branches plant-1, a number of siliqua plant-1 and a number of seeds siliqua-1 indicating the effects of additive genes in controlling the traits. Significant and positive association with seed yield plant-1 were observed in the number of primary branches plant-1, a number of seeds siliqua-1, while a negative association was found in days to maturity. The path analysis revealed that the days to first flowering, number of secondary branches plant-1 and 1000 seed weight were the main contributors to seed yield. The results suggest that days to first flowering, number of primary and secondary branches plant-1 and 1000 seed weight may be considered for selection to improve the seed yield in B. rapa. Journal of Bangladesh Academy of Sciences, Vol. 44, No. 2, 95-107, 2020

Assessment of Tomato Recombinant Lines in Conventional and Organic Farming Systems for Productivity and Fruit Quality Traits

It is estimated that more than 95% of organic agriculture is based on crop cultivars that were bred for the conventional high-input sector. Most selections were made through conventional breeding programs and lack important traits required under organic and low-input conditions. Hybrids are the most common type of cultivars used in tomato because of heterosis. In tomato, continuous selfing enabled homozygosity to exploit favorable additive genes, resulting in the so-called inbred vigor. This paper presented the possibility to express inbred vigor at a level equal to or greater than hybrid vigor in tomato when cultivated under organic low input conditions. The evaluation of the recombinant lines produced through classical reverse breeding from four F1 single cross hybrids was done at low- and high-input farming systems. The results show that, following the appropriate breeding process in early generation selection and under low-input conditions, it is possible to produce recombinant lines, demonstrating inbred vigor in yield potential and fruit quality. These genetic materials can stand as new dynamic cultivars intended for cultivation in organic, low-input, or high-input conditions, depending on their performance in different farming systems at the later stages of evaluation.

ГЕНЕТИЧЕСКИЕ АСПЕКТЫ ФОТОСИНТЕЗА АРОМАТИЧЕСКИХ СОРТОВ ТАБАКА И ПУТИ ОПТИМИЗАЦИИ СЕЛЕКЦИИ: КОЭФФИЦИЕНТ ФОТОСИНТЕТИЧЕСКОЙ ПРОДУКТИВНОСТИ

The results of genetic analysis on the coefficient of photosynthetic productivity (CPP) in seven varieties of Samsun tobacco are summed up in the fourth article of the series. It has been confirmed that in the hybrids of F1 an intermediate inheritance of the trait prevails, which is mainly manifested by the impact of recessive additive genes leading to incompatibility in the indices of ĝi and the mentioned trait. The significance of CPP as a valuable photosynthetic index in the creation of hybrid combinations with an improved photosynthetic apparatus has been justified. In the result of the study, valuable varieties and perspective hybrids have been identified and specific recommendations on optimizing all breeding stages have been introduced.

Combinational ability of crossing components and heterosis of F1 hybrids of sugar sorghum by biomass yield

Currently, the most promising direction of breeding is the creation of F1 hybrids of sugar sorghum, based on the identification and selection of parental forms with high combinational ability. The source material and F1 hybrids were grown in the arid conditions of the Saratov Right Bank (Russia): the hydrothermal coefficient during the growing season was 0.68. The evaluation of the combinational ability of crossing components was carried out using the topcross method. As a result of the tests, the L-52/13 line was identified with high GCA effects (15.71), and the highest SCA dispersions were found in the Saratovskoe 90 variety and the L-39/12 line (91.80-189.27). It was found that the type of sterile cytoplasm of iso-nuclear CMS-lines had a significant impact on the manifestation of SCA in terms of biomass yield: higher dispersion indicators were noted in 9E Zheltozernoye 10 (36.66). Genes with an additive effect are involved in the genetic control of this trait in paternal forms, and non-additive genes in maternal forms. In addition, each hybrid combinationwas observed with superdomination: the coefficient of phenotypic dominance varied from 2.01 to 18.91. It is advisable to use the obtained information in the hybridization of sugar sorghum to obtain high-heterosis hybrids.

Combining ability and heterosis for yield, precocity and height in yellow maize genotypes

The objective of the present study was to determine the general combinatorial aptitude (GCA), specific combinatorial aptitude (SCA) and heterosis in inbred lines of yellow maize and its crosses for, the yield of grain, height of plant and ear and days to male and female flowering. Six inbred lines from CIMMYT, their direct crosses and four controls were evaluated at UNALM during 2016-2018, under a 5 x 5 lattice design with four repetitions. The effects of GCA and SCA were calculated using method II, model I of Griffing. Heterosis was measured based on the mean and best parent. Heterosis was measured based on the mean and best parent. The combined analysis of years showed significance (p ≤ 0.01) in: genotypes by years for days to male and female flowering; GCA for years for days to male flowering and SCA for years for days to female flowering. The effects of ACG for grain yield were significant in lines CML 229 and CML 428, for plant height, precocity, ear and precocity CML 487 line highlighted. The effect of ACE was superior in the cross CML 453 x CML 486 for the grain yield character. Heterosis was higher for the grain yield in the CML 229 x CML 453 and CML 453 x CML 487 crosses. The GCA / SCA relationship evidenced effects of additive genes on plant height, days to male and female flowering, therefore, for grain yield and ear height, non-additive effects governed.

GENOTYPE-ENVIRONMENT INTERACTIONS AND INHERITANCE OF QUANTITATIVE TRAITS IN A HYBRID COMBINATION BETWEEN SEEDED AND SEEDLESS GRAPEVINE CULTIVARS (VITIS VINIFERA L.)

The genotype–environment interactions and the inheritance of quantitative traits in a hybrid combination between a seeded grapevine cultivar and a seedless one (Armira × Rusalka 1) have been studied. It has been found that the selection of valuable hybrid forms shall become more efficient when conducted according to the traits ‘flowering – berry softening’, ‘berry softening – technological maturity’, ‘cluster weight’, ‘weight of 100 berries’ and ‘acids’. Dominant gene interactions with the environment are characterized by significantly greater intensity in comparison to those of additive genes. Inheritance in F1 progeny manifests very high values for the traits ‘budding’, ‘flowering’, ‘budding – flowering’, ‘flowering – berry softening’, ‘berry softening – technological maturity’, ‘berry length’. ‘berry width’, ‘weight of 100 berries’, ‘sugars’ and ‘acids’. According to the genetic stability of the dominant parameter interacting with the environment, a comparative evaluation can be made for each trait and, depending on the selection purpose, elite hybrid plants can be singled out, which possess a combination of the most important commercial traits.

Analisis Daya Gabung dan Korelasi Karakter Jumlah Buah Kakao pada Persilangan Setengah Dialel

<em>Analysis of combining ability and correlation between characters in cacao plays an important role and benefits in an effort to obtain superior high-yield genetic material. This analysis makes it easy to find out the best combination of parents in producing superior progeny. The study aimed to analyze the combining ability and correlation of cacao pod numbers in F1 population generated from half-diallel crossing. The study was conducted at Pakuwon Experimental Station, Sukabumi, West Java, at an altitude of 450 m above sea level with Latosol soil type and B climate type (Schmidt and Fergusson), from 2014 until 2018. The experiment was arranged using a randomized block design (RBD) with 10 combinations of half-diallel crossing method that were repeated three times. The parental genotypes used were ICCRI 03, TSH 858, DR 1, ICS 13, and SCA 6. The variables observed were the number of healthy pods, number of rotten pods, number of cherelle wilts, and total pod numbers. The combining ability was analyzed using the Griffing 4 method, while correlation analysis was carried out phenotypically and genotypically.The results showed the action of non-additive genes in the F1 generation and three combinations of crosses, namely ICCRI 03 x TSH 858, TSH 858 x DR 1, and ICS 13 x SCA 6 had the opportunity to be developed into superior hybrids. In addition, it is known that there were phenotypic and genotypic positive correlations between the observed pod component characters.</em>