Cytological elucidation of somaclonal variation in grasspea (Lathyrus sativus L.)

Abstract

A cytological study of root tips, primary calli, sub-culture calli and regenerants of grass pea (Lathyrus sativus L) cv. Nayagarh local was carried out for elucidation of the origin of tissue culture instability and somaclonal variation. Wide range of euploids, aneuploids and structural variations of chromosomes including stickiness, multipolar spindle, asymmetric chromatid separation, binucleate cells with micronuclei and chromosome bridges and fragments could be the cause for tissue culture instability. Frequency of chromosomal anomalies in calli increased with the age of subculrure and the increase was more in B5 medium supplemented with 2, 4-D than NAA. Majority of the abnormalities happens to be sieved off owing to morphogenetic selectivity. While, a few of these were carried on to regenerants as evidenced from mitotic (euploid, aneuploid and structural variation) and meiotic (interchanges and/or loss of chromosome segments following breakage events, lack of pairing resulting univalents, precocious and late separation of bivalents, anaphase laggards, conspicuous anaphase bridges with or without acentric fragments, chromosome rings, tetrad with multinucleoli) abnormalities in regenerants. Such carryover events have been substantiated as the origin of somaclonal variation in regenerants.

Case Study of Somaclonal Variation in Resistance GenesMloandPme3in Flaxseed (Linum usitatissimumL.) Induced by Nanoparticles

“…Although callus culture consists of undifferentiated fast dividing cells which results in high somaclonal variation level, regenerants from callus culture inherits only part of callus cell's genetic material. This is through the fact that embryo is formed only from one undifferentiated cell from callus culture [ 25 ]. No doubt, the number of analysed regenerants in each group was less than the number of analysed calluses, but the major differences in genetic variability were observed in each sequence.…”

Current Perspectives on Reducing the β-ODAP Content and Improving Potential Agronomic Traits in Grass Pea (Lathyrus sativus L.)

“…Among the different explants of grass pea, the epicotyl was reported to be the most responsive with high shoot proliferation frequency. Development of somaclones in L. sativus is limited (Santha and Mehta, 2001;Tripathy et al, 2016;Barpete et al, 2020a), but in India, such efforts have developed somaclones derived low-ODAP variety (Ratan) (Mehta et al, 1994;Santha and Mehta, 2001). Tripathy et al (2016) have also developed a series of somaclones for morphological, cytological (genetic) variation, and biochemical levels in four grass pea (Nirmal, P 24, Nayagarh local, and Dhenkanal local) genotypes.…”

“…A high-yielding and low ODAP somaclone (cv. NGOG 5) was developed that may be the potential candidate for future grass pea breeding programs (Tripathy et al, 2016). Ochatt et al (2002) and Barpete et al (2020a) developed an in vitro system for shortening the generation cycles and hastening the breeding process coupled with the in vitro stages that provide up to 4-5 cycles per year of grass pea.…”