HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Hill, R. R. Articles by Zeiders, K. E. Search for Related Content PubMed Articles by Hill, R. R., Jr. Articles by Zeiders, K. E. Agricola Articles by Hill, R. R. Articles by Zeiders, K. E.

Combining Ability Among Four-Clone Alfalfa Synthetics¹

Two groups of experimental alfalfa (Medicago sativa L.) synthetics were produced, 36 synthetics from 10 related parents in one group and 24 synthetics from nine unrelated parents in the other. Combining ability variances were estimated for spring growth, yield, recovery after the first harvest, fall growth, stand, and frost damage in a field experiment, and for reaction to seven pathogens in greenhouse experiments.

Significant general combining ability variance was detected for spring growth, yield, recovery after the first harvest, and for reaction to Colletotrichum trifolii Bain and to Pseudopeziza medicaginis (Lib.) Sacc. in both groups of synthetics. General combining ability variance for stand, and reaction to Phoma herbarum West f. medicaginis West ex. Rab., Uromyces striatus Schroet. var. medicaginis (Pass.) Arth., and to Corynebacterium insidiosum (McCull.) Jens, were significant in one or the other of the two groups. Significant specific combining ability variance was observed for yield, stand, frost damage, and reaction to C. trifolii, U. striatus, and C. insidiosum in one or the other of the groups. Significant combining ability variances were not detected for reaction to Stemphylium botryosum Wallr. and Leptosphaerulina briosiana (Poll.) Graham and Luttrell in either group of synthetics. We concluded that specific combining ability variations in the four-clone alfalfa synthetics in both groups were so small that breeding procedures that operate on additive gene action would be more effective in development of improved synthetics than attempting to utilize specific combining ability effects by screening numerous experimental synthetics.

Key Words: Forage breeding • Forage yield • Disease resistance • Medicago sativa L.

² Research Agronomist, Research Plant Pathologist, and Plant Pathologist Research Assistant, U.S. Regional Pasture Research Laboratory, University Park, Pa. 16802.

Received for publication February 25, 1972.