Genetic and pollen studies in Gladiolus spp

Abstract

Gladiolus is one of the important bulbous ornamentals grown in many parts of the world. In India it has now gained importance as a cut flower for domestic consumption and also for export. A study was carried out at IIHR, Bangalore to generate information on genetic and pollen related characters in Gladiolus spp. Studies on the relative performance of India (11) and exotic (24) Gladiolus genotypes showed that Indian cultivars were early in spike emergence, had more florets per spike, more spikes per corm, high corm multiplication rate, larger corms, more viable pollen and short flowering duration. While, exotic genotypes had larger florets, more florets open at one time, longer spikes and high cormel multiplication rate. Since, exotic cultivars exhibited better spike/floret characters which are of economic importance they may be grown on a commercial scale. High phenotypic and genotypic co-efficient of variation, heritability and genetic advance recorded for number of shoots per plant, number of spikes per corm, number of daughter corms, number of cormels percorm, 25 cormel weight and propagation co-efficient suggests selections of genotypes based on these traits for further improvement through effective breeding programmes. Studies on the association of various morphological traits through correlation and path co-efficients analysis showed that, plant height, spike girth, number of florets open at one time, florets length, weight of daughter corm and rachis length had positive and significant correlations with maximum direct effects on number of florets per spike. While leaf number, floret diameter and spike length though had positive and significant correlations. Spike weight, and equatorial corm diameter had maximum indirect effects with significant and positive correlations. Number of daughter corms had significant positive association and direct effects on number of shoots per plant and 25 cormel weights. While, number of shoots per plant through had significant and positive correlation, it exhibited maximum indirect effect. The feasibility studies on storing pollen from five promising varieties viz., Darshan, Dhiraj, Sagar, Sapna and Shobha developed at IIHR and G. callianthus a wild fragrant species at sub zero temperatures of -65 oC and -196 oC (in liquid nitrogen) showed negligible loss in the viability, vigour and fertility levels of pollen (from all the genotypes) upon storage compared to fresh pollen. Hence, there are no species/varietal specific pollen storage temperatures.