Genetic variability, heritability, and diversity analysis in short day tropical onion (Allium cepa)

Abstract

The main aim of the present investigation was to assess the degree of variability, heritability and genetic advance in onion (Allium cepa L.) using 13 quantitative and four biochemical traits. PCV was higher than GCV for all the traits but the difference was less in plant height, pyruvic acid, leaf length, number of leaves, pseudostem length, pseudostem width, leaf width and total phenols indicating higher contribution of genotypic effect towards phenotypic expression. Highest heritability was observed for plant height, number of leaves, leaf length, leaf width, pseudostemlength, pseudostem diameter, total phenols and pyruvic acid. High heritability along with high genetic advance as percent of mean was recorded in number of leaves, leaf length, leaf width, pseudostem length, pseudostem diameter, total phenols and pyruvic acid indicating the presence of additive gene action for the expression of these traits. Based on Euclidean distance and Ward’s minimum variance, all accessions were clustered into four groups. Cluster I comprised of accessions with highest yield, yield related traits and high pungency. Cluster II was the largest cluster and composed of accessions having highest TSS and dry matter content. Cluster III was the smallest cluster comprising ofaccessions having highest polar diameter and total phenols. Cluster IV comprised of accessions having low yielding potential. Five principal components (PC1 to PC5), having latent roots greater than one, accounted for 78.5% total variation. Cluster analysis and Principal component analysis (PCA) were in agreement for assigning genotypes into four clusters. In the first principal component, plant height, leaf length and pseudostem diameter were the most contributing traits, whereas dry matter, total soluble solids (TSS) and pyruvic acid were the principal traits of the second principal component. Based on squared cosine value (Cos2) for variables, average bulb weight, gross yield and marketable yield in positive direction and plant height, leaf length and pseudostem width in negative direction, were the major contributing traits. Squared cosine value (Cos2) for individual factor determined that Superex and Black Gold were the most prominent genotypes contributing towards PCA. This study would provide a better opportunity to select potential genotypes for yield related traits and help breeders in precise selection of promising diverse parents for purposeful heterosis breeding.

Characterization of the genetic structure of a cupuassu tree population collected in primary forest

“…Studying genetic diversity from these traits will provide lower residual effects and more reliable results. If there is interest in selecting genotypes for any of these characters, the gains from selection will be of great magnitude (Dangi et al, 2018).…”

Keragaman genetik dan heritabilitas 12 genotipe bawang merah (Alllium cepa L. var Aggregatum) di dataran tinggi

“…Penampilan tanaman berbeda pada kondisi iklim yang bervariasi dan varietas dari spesies yang sama yang dibudidayakan di lingkungan yang sama memberikan hasil yang berbeda karena potensi tanaman tergantung pada interaksi genetik dan lingkungan (Visalakshi et al, 2018) Informasi mengenai keragaman genetik dan heritabilitas bawang merah di Indonesia masih sangat terbatas. Hasil penelitian mengenai keragaman genetik dan heritabilitas sudah dilakukan pada bawang merah, di Indonesia oleh Herlina et al (2019); dan Herlina et al (2018); di Ethiophia oleh Degewione et al (2011); dan bawang bombay (Allium cepa L.) di India oleh Solanki et al (2015), dan Dangi et al (2018). Oleh karena itu perlu dilakukan penelitian mengenai keragaman genetik dan heritabilitas bawang merah.…”

“…Hal ini sejalan dengan penelitian Degewione et al (2011) pada bawang merah KKG dan KKF dengan keragaman sedang terdapat pada diameter umbi, lebar daun, hasil umbi per rumpun, jumlah anakan, tinggi umbi dan kepedasan. Dan pada bawang bombay penelitian Solanki et al (2015) jumlah daun per tanaman dan ketebalan leher; penelitian Dangi et al (2018) jumlah daun, panjang daun, lebar daun, tinggi batang semu, dan diameter batang semu, sedangkan pada bawang putih (Singh et al, 2018) ketebalan leher umbi, hasil umbi per tanaman, jumlah siung per umbi, berat per siung dan diameter siung pada bawang putih. Keragaman sedang menunjukkan adanya keragaman yang relatif moderat untuk karakter-karakter tersebut, yang dapat dimanfaatkan untuk perbaikan melalui seleksi pada generasi lanjut (Nirmaladevi et al, 2015).…”

“…Hal yang sama dilaporkan pada bawang merah (Degewione et al 2011), kacang hijau (Hapsari, 2014); padi (Nirmaladevi et al, 2015), bawang bombay Dangi et al (2018), pada sawi (Muhammad & Waluyo, 2019). Nilai KKF lebih tinggi daripada nilai KKG menunjukkan faktor lingkungan mempengaruhi karakter ini (Dangi et al, 2018) Keterangan: R=rendah; S=sedang; T=tinggi; SM=sempit; L=luas Tetapi jika perbedaan nilai KKG dan KKF yang sempit (<1) pada masing-masing karakter menunjukkan keragaman suatu karakter lebih disebabkan faktor genetik yang mengindikasikan resistensi relatif mereka terhadap keragaman lingkungan lingkungan (Dangi et al, 2018 ;Solanki et al, 2015)). Hal ini dapat disebabkan karena materi yang diuji berbeda latar belakang genetik (Hapsari, 2014) dan seleksi dapat dilakukan secara efektif melalui keragaman fenotipik.…”

Genetic Variability and Diversity in Red Onion (Allium cepa L.) Genotypes: Elucidating Morpho-Horticultural and Quality Perspectives

“…Genetic variation lies in the foundation of plant breeding and is the 'must-have' for any improvement programme. The components of variability like heritability (h 2 ), genetic gain, phenotypic co-efficient of variation (PCV), and genotypic co-efficient of variation (GCV) are important biometric tools for judging heterogeneity in any population, which makes the selection and evaluation of onion germplasm easier for improvement [11,12]. Furthermore, the perception of yield and its relationship to the other contributing traits is a crucial element in improving onion yield, particularly through selection.…”