No abstract

KS108GH5 alfalfa germplasm Reg. no. was released by the USDA-ARS, and the Kansas Agricultural Experiment Station in February 1985. It is resistant to the blue alfalfa aphid (Acyrthosiphon kondoi Shinji), pea aphid [Acyrthosiphon pisum (Harris)], spotted alfalfa aphid [Therioaphis maculata (Buckton)], potato leafhopper, Empoascafabae (Harris), anthracnose (caused by Colletotrichum trifolii Bain), and downy mildew (caused by Peronospora trifoliorurn d By). KS108GH5 was derived from the original seed of PI346919, a plant introduction from Russia. It was labeled Medicago glutinosa. Later, Gunn et al.(1) identified it as a mixture of the following Medicago sativa L. subspecies: sativa, praefalcata, glornerata, and X varia. The population was characterized by erect glandular hairs on the seed pods and eglandular vegetative organs. We conducted five cycles of recurrent phenotypic selection for erect glandular hairs on the vegetative parts. Seven percent of the first and 100% of the fifth-cycle plants had erect glandular hairs on the vegetative parts. Hair density varied widely among plants in the KS108GH5 population but plants with a high density of hairs on the vegetative parts were prevalent.Seedling tests to evaluate resistance to the blue alfalfa aphid, pea aphid, spotted alfalfa aphid, and downy mildew were conducted at Manhattan, KS.Percentages of resistance to aphid biotypes in Kansas were: spotted alfalfa aphid-KSI08GH5 = 89, 'Kanza' (resistant control) = 80, 'Ranger' (susceptible control) =10; blue alfalfa aphid-KSI08GH5 = 43, 'CUF 101' (resistant control) = 47, 'Buffalo' (susceptible control) = 0; pea aphid-KS108GH5 = 69, Kanza (resistant control) = 56, Ranger (susceptible control) = 0.Germplasm KS108GH5, resistant con susceptible control Kanza showed the ages of resistant plants in tests with th fungus isolates: 15-KS108GH5 = 44, S = 2; I7-KS108GH5 = 16, Saranac I8-KS108GH5 = 59, Saranac = 58, anthracnose (race 1) seedling test at R centages of resistant plants were: KS10 (the resistant control) = 76, and the S control) = 10.The KS108GH5 germplasm has not resistance to the potato leafhopper. Ho hair density of 5 per mm 2 on the stem by leafhoppers in the field or in grow those without hairs were severely dama Two grams of KS108GH5 seed are a plicant upon written request and agree ately recognize its source as a matter of this germplasm contributes to the dev cultivar or hybrid.Seed stocks of KS108GH5 syn 2 are Department of Agronomy, Kansas Sta hattan, KS 66506.

No abstract

Two populations of alfalfa (Medicago sativa L.) regenerated from nonmutagenized mesophyll protoplasts were compared to their parent clones (RS‐K1 and RS‐K2) for changes in phenotype and in chromosome complement. Thirty and 45% of RS‐K1 and RS‐K2 protoclones, respectively, had 32 chromosomes (2n = 4x = 32). Chromosomal changes observed included increased ploidy, aneuploidy, and translocations. Some protoclones were more susceptible to winter damage than were their parents, and various other phenotypic changes were observed. Dry weight forage yields for four harvests were obtained from ramets in replicated field plots the year after transplanting. Protoclones significantly superior, equal, and inferior (P = 0.05) to their respective parents were obtained, with the latter two classes greatly predominating. Between the third and fourth cuttings, a crown rot killed 60% of the protoclones. Fusarium solani and/or F. roseum and Rhizoctonia solani were isolated from these plants. One RS‐K2 protoclone appeared to exhibit resistance under this naturally‐occurring epidemic.

Field plots of alfalfa, Medicago sativa L., sprayed weekly with Dithane M‐45 during the 1965 growing season to control leaf and stem diseases yielded 2.8 MT/ha (18%) more hay than did unsprayed plots (Average of four varieties in four cuttings). Disease control increased carotene content 21% (third cutting) and decreased stem defoliation 18%. Increases in annual forage yields in MT/ha, for sprayed over unsprayed plots, respectively, were ‘Cody’ 1.57 (8.8%), ‘Lahontan’ 3.47 (21.1%), ‘Ranger’ 3.11 (19.4%), and ‘Vernal’ 3.11 (26.9%).Phoma medicaginis and Leptosphaerulina briosiana were the major pathogens in the first and second cuttings. Their control increased yields of Cody 4%, Lahontan 14%, Ranger 19%, and Vernal 19% for the first two cuttings combined. Cercospora zebrina was the principal pathogen in the third and fourth cuttings. Control of C. zebrina increased yields of Cody 16%, Ranger 29%, Lahontan 30%, and Vernal 38% for the third and fourth cuttings combined. Corresponding increases in carotene content for the third cutting were 17, 20, 45, and 10%, respectively.Defoliation was reduced by spray treatments. Protein percentage was not affected.