Genetic diversity within Gerbera jamesonii Bolus is the key to genetic improvement of this important ornamental species. In the present study, genetic diversity of 12 accessions of gerbera was assessed through random amplified polymorphic DNA (RAPD) markers. A total of 40 RAPD primers belonging to OPD, OPE, OPF and OPG series of universal primers set were used out of which, only 10 primers produced clear, reproducible and scorable bands. Ten (10) decamer RAPD primers produced a total of 49 scorable bands from 12 genotypes of G. jamesonii Bolus, out of which 42 were polymorphic and seven were monomorphic. The percentage of polymorphism ranged from a maximum of 100.00% by OPE-02, OPE-14, OPF-18, OPG-18, OPG-16 and OPG-17 to a minimum of 50.00% by OPE-08. The RAPD profiles generated were further evaluated for studying the Jaccard's similarity coefficient. The average genetic similarity coefficient for the 12 accessions evaluated by Jaccard index was 0.66 ranging from 0.35 to 0.86. The RAPD amplification data were used to obtain similarity matrix and for generation of dendrogram using unweighted pair group method with arithmetic averages (UPGMA) method. Based on the dendrogram, all 12 genotypes could be distinctly divided into two clusters and the accession CF Orange was found most dissimilar from other accessions. This study shows that DNA based molecular marker RAPD is a powerful, less time consuming and cost effective molecular technique for assessment of genetic diversity among different genotypes of G. jamesonii Bolus. The availability of these gerbera RAPD markers would facilitate the use of molecular markers in gerbera breeding and genetic studies.

SINGH, A.B., and CHATURVEDI, C.M. 1993. Effect of altered thyroid and adrenal activity on the seasonal reproduction of the Indian palm squirrel, Funambulus pennanti. Can. J. Zool. 71 : 1558 -156 1. Thiouracil and metyrapone administered during the progression phase of the annual reproductive cycle inhibited gonadal development in the Indian palm squirrel, Funambulus pennanti. In a further experiment, these drugs led to normal gonadal regression during the late breeding phase. Thyroxine and corticosterone treatment, on the other hand, maintained the gonads continuously in breeding condition, unlike those of controls, which exhibited characteristic post-reproductive regression. Since hypofunction of the thyroid and adrenal glands had inhibitory effects on the initiation of seasonal gonadal growth, and hyperactivity affects post-reproductive regression, it is suggested that an optimal level of hormones is required for the normal breeding cycle in this subtropical mammal. The results are discussed in terms of an interrelationship between the seasonal thyroid, adrenal, and gonad cycles under natural conditions. SINGH, A.B., et CHATURVEDI, C.M. 1993. Effect of altered thyroid and adrenal activity on the seasonal reproduction of the Indian palm squirrel, Funambulus pennanti. Can. J. Zool. 71 : 1558-1561. Au cours d'une experience, l'administration de thiouracil et de metyrapone au cours de la phase de progression du cycle annuel de reproduction a eu pour effet d'inhiber le developpement des gonades chez 1'Ecureuil des palmes, Funambulus pennanti. Au cours d'une autre experience, l'administration de ces drogues durant la dernikre phase de la reproduction a donne lieu a une regression normale des gonades. En revanche, un traitement a la thyroxine et a la corticostCrone a assure le maintien de 1'Ctat reproducteur de la gonade, alors que les gonades des Ccureuils temoins ont subi la regression post-reproductrice caractkristique. Comme un hypofonctionnement de la thyro'ide et des surrenales a des effets inhibiteurs sur le declenchement de la croissance gonadique saisonnikre et puisque l'hyperactivite affecte la regression des gonades, on peut supposer qu'il existe une concentration optimale des hormones pour que le cycle de la reproduction soit normal chez ce mannifkre subtropical. Les resultats sont examines a la lumikre des relations qui prevalent entre les cycles saisonniers de la thyro'ide, des surrenales et des gonades dans des conditions naturelles.[Traduit par la ridaction]

No abstract

No abstract

The present study was undertaken to know the effects of salinity on nodulation and leghemoglobin content in two cultivars (NDM-17 and Pusa Kasauri) of fenugreek (Trigonella foenum-greacum L.) treated with rhizobium. The pot experiments were conducted following completely randomized block design method. Two sets of pots were maintained with one set treated with rhizobium and other without. The sets were irrigated with saline water of different electrical conductivities (0.2, 3.2, 6.2, 7.2, 10.2, 12.2 and 14.2 dSm-1) created with NaCl, Na2SO4, NaHCO3 and CaCl2 salts. Observations on nodules number, weight and leghemoglobin content were recorded 30, 60, 90 and 120 days after sowing . The nodules growth decreased with increasing levels of salinity. Seeds treated with rhizobium ameliorated the deleterious effect of salinity at all levels besides improving the fertility of soil and growth of root nodules by nitrogen fixation. Present findings revealed that maximum number, weight and leghemoglobin content in cv. NDM-17 was higher as compared to cv. Pusa Kasauri in both treated and non-treated with rhizobium indicating it be the tolerant of the two cultivars.