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 Blum, A. Search for Related Content PubMed Articles by Blum, A. Agricola Articles by Blum, A.

Basis of Heterosis in the Differentiating Sorghum Panicle¹

Heterosis in grain sorghum (Sorghum bicolor L. (Moench)) yield has been previously traced to heterosis in the number of grains per basal branch in the panicle. A comparative quantitative morphogenetical study of the differentiating panicle was performed to explore the origin of this heterotic effect. Field grown plants of RS 610 hybrid and its two parental lines (B-Combine Kafir 60 and Tx 7078) were dissected and studied microscopically.

Heterosis (advantage of the hybrid over both parental lines) was identified in faster formation of primary and secondary panicle branches; faster panicle growth rate and larger primary basal branch primordia. The hybrid did not differ from the parental lines in the number of branch whorls per panicle, growth rate of basal primary branches, and the length of time period between spikelet and floret initiation.

Heterosis in the number of grains per basal primary branch was traced to two major factors: (1) a larger reproductive apex that allowed development of larger basal branch primordia, and (2) a 4-day time-lapse between termination of the acropetal formation of branches and the onset of the basipetal formation of spikelets. This time-lapse was utilized in the hybrid for the increase in basal branch size prior to spikelet initiation.

Key Words: Sorghum bicolor L. (Moench) • Hybrid vigor • Flowering

² Visiting associate professor, presently at the Volcani Center, ARO, P.O.B. 6, Bet Dagan, Israel.

Received for publication April 18, 1977.