Seed Yield is not Impaired by Chromosome Stickiness in Sodium Azide Treated Trigonella foenum-graecum

Abstract

Summary Partial or complete stickiness of chromosomes and disorientation of spindle were the major anomalies observed in meiocytes of Trigonella plants raised from seeds treated with different concentration of sodium azide for three durations. Other aberrations were unequal separation, non synchronous division, bridge, laggard, stray etc. The pollen fertility and yield showed an increase over control despite the high frequency of stickiness and spindle disorientation. Yield was positively correlated with stickiness, indicating a balancing/regulatory effect of stickiness at the time of gamete formation. Meiosis, an event of high evolutionary stability, plays a dual role as it halves the chromosome number in order to maintain ploidy level after fertilization and also ensures viability of gametes. It is a major event in the life cycle of any individual and a normal and harmonious completion of the cytological action is controlled by large number of genes, which act from pre-meiotic to post-meiotic stage. Mutation in these genes causes abnormalities that may or may not impair pollen fertility. Key wordsCytological studies constitute an important component in a breeding program involving the development of new original forms with the aid of experimental mutagenesis. The normal and harmonious course of meiosis ensures gamete viability, which if altered has a significant affect on the yield. The objective of this work was to study the meiotic behavior in pollen mother cells of sodium azide treated Trigonella foenum-graecum plants. The different concentrations of sodium azide caused meiotic abnormalities in high numbers, but surprisingly did not affect the pollen fertility and yield. The yield was significantly increased at some doses, contrary to the belief that aberration leads to abnormal gametes and hence low yield. Sodium azide has been reported to induce large variability for several characters viz. number of capsules per plant, number of seeds per capsule, size of the seeds and weight of 100 seeds in Capsicum annuum and mutants also exhibited high germination percentage and vigour over parental variety (Umalkar et al. 1981). The suitability of sodium azide, as a mutagen for T. foenum-graecum was investigated by assessing the type of cytological anomalies and correlating it with the seed yield per plant. Materials and methodsDuring our investigation, uniform sized seeds were treated with 0.10%, 0.15%, 0.20% and 0.25% freshly prepared sodium azide solution (pHϭ4), each for different durations (2 h, 4 h and 6 h) and the treated seeds after proper washing were sown along with control in pots. For meiotic studies, flower buds were taken from plants of each treatment. Appropriate sized flower buds were fixed in 1 : 3 iron saturated acetic acid and absolute alcohol for 24 h and there after transferred to 70% alcohol. Slides were prepared by squashing the anthers in Acetocarmine stain, gently heated to

Chromosomal Induced Aberrations in Sunflower (Helianthus annuus. L) with Gamma-irradiation, Sodium Azide and Combined Treatments

“…In analysed meiospores of control plants normal bivalent formation was observed as also reported by Srivastava and Kavita Kapoor (2008) in Trigonella foenum-graecum, Pagliarini (1990) in Aptenia cordifolia, Defani Scoarize et al (1995a, b) in maize, Consolaro et al (1996) in Centella asiatica L. As the radiation doses increases, the percentage of abnormal cell increased by Zeerak (1992) in tomato, Ahmad (1993) and Khare (1994) in Cicer arietinum L., as it is also reported in sunflower in the present investigation. In mutagenised population of USH-430 at 6 kR and KL-675 at 6 kR treatment the analysed meiospores in 1 plant exhibited quadrivalents as it was reported by Bose and Saha (1970), Ratnam and Madhava Rao (1992).…”

Assessment of Gamma Rays Induced Cytotoxicity in Common Wheat (<i>Triticum aestivum</i> L.)

“…Srivastava and Kapoor (2008) reported that precocious chromosome migration to the poles may be due to the formation of univalent chromosomes at the end of prophase I or due to precocious chiasma terminalization at diakinesis or metaphase.…”

Efficiency and Effectiveness of Gamma Rays and Sodium Azide in <i>Sesbania cannabina</i> Poir.

“…tarar and Dnyansagar (1980) have reported that stickiness at meiosis is due to the depolymerisation of nucleic acids caused by mutagenic treatments; or, it may be due to chemically induced stickiness to direct action of mutagens on the histone proteins leading to improper folding of Dna (gaulden 1987). Bridges are also induced by many other mutagens, such as methyl methane sulphonate (Khan and al-Qurainy 2009), and Sa (Srivastava and Kapoor 2008), etc. Precocious movement of chromosomes may be due to spindle dysfunction.…”