Genetic improvement of pyrethrum

Abstract

Pyrethrum (Chrysanthemum cinerariefolium), an important paramedicinal plant is a potential source of pyrethrins, which have a long history of safe uses against mosquito larvae - a carrier of malarial parasite. It was introduced in India from Kenya in 1931. Considerable genetic diversity has been generated over the years. Repeated clonal selection could lead to isolation of a number of divergent clones representing selective divergence. Planned hybridization among some of the chosen clones could further enlarge the spectrum of variation as measured by multivariate analyses (D(2)-statistic and canonical analysis). The resulting hybrids manifested a variable degree of heterosis which was found to be, by and large, positively associated with the degree of divergence between the two constituent parents of a hybrid. However, the choice of the potential hybrid clone(s) for commercial exploitation was most viable when parents for hybridization were short-listed on the basis of parental divergence coupled essentially with per se performance for specific traits. The latter criterion assumes greater significance since low x low or medium x low parental hybrids also tended to register high heterosis for both the pyrethrins content and yield. Four hybrids: 234xL, 8xL, 326×395 and 319xL were identified to be the most promising for clonal selection.

Effect of soil type on pyrethrum seed germination

“…Breeding programmes have obtained pyrethrum seeds with a germination capacity of 80% (Fulton et al 2001), while wild population seeds have a lower germination capacity. Generally, breeding programs are primarily directed at increasing the concentration of active compounds (Singh and Sharma 1989). So far, experiments have shown that total pyrethrins content of natural Dalmatian pyrethrum are lower than those obtained from commercial selected varieties (Ban et al 2010;Grdiša 2013).…”

Breeding of New Ornamental Varieties:Rose

“…For development of a new variety, creation of genetic variability is a pre-requisite. Genetic diversity plays an important role in breeding because hybrids between genetically diverse parents manifest greater heterosis than those between closely related parents [11][12][13][14] . A number of plant breeding methods like cross-breeding, induced mutagenesis and molecular breeding play an important role in the development of new varieties.…”

Breeding of Ornamentals:Tuberose (<i>Polianthes tuberosa</i> L.)

“…Creation of genetic variability is pre-requisite for development of new variety. Genetic diversity plays an important role in breeding because hybrids between genetically diverse parents manifest greater heterosis than those between closely related parents [1][2][3][4] . It is important to understand the science behind flower colour inheritance, polyploidy, and potential sterility of one or more parents before hybridization.…”