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ARS Home » Midwest Area » Columbia, Missouri » Plant Genetics Research » Research » Publications at this Location » Publication #68042
Title: ALTERATION IN THE TIMING OF VEGETATIVE PHASE ASSOCIATED WITH NINE CYCLES OF DIVERGENT SELECTION FOR RIND PENETROMETER RESISTANCE IN MISSOURI STIFF STALK SYNTHETIC

Author
item ABEDON, B - UNIV OF WISCONSIN
item Darrah, Larry
item TRACY, W - UNIV OF WISCONSIN

Submitted to: Maize Genetics Cooperation Newsletter
Publication Type: Research Notes
Publication Acceptance Date: 9/3/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Vegetative development in maize can be divided into juvenile (basal) and adult (distal) phases, each with distinct morphology and physiology. Variation in the timing of developmental phases (heterochrony) has adaptive value and evolutionary importance in a number of plant species. Efforts by ARS at the University of Missouri to develop stalk lodging resistant germplasm have focused on recurrent selection for rind penetrometer resistance (RPR) in Missouri Stiff Stalk Synthetic (MoSSS). Our objectives were to investigate developmental changes associated with nine cycles of divergent selection for RPR in MoSSS. Last leaf with juvenile wax showed an increasing trend while tiller number increased significantly between C9high and C9low, indicating that selection for high RPR truncated the juvenile phase while selection for low RPR elongated the juvenile phase. First leaf with adult wax increased significantly between C9high and C0 but did not change between C0 and C9low. First leaf with pubescence increased significantly from C9high to C9low. These results indicate the selection for high RPR resulted in a faster initiation of the adult-vegetative phase, while selection for low RPR delayed the onset of pubescence without affecting the first leaf with adult wax (suggesting that these traits are regulated independently). These results indicate that no relationship exists between the timing of vegetative and reproductive phases in these populations. Ear and plant height decreased significantly in both directions of selection while no significant difference was observed for last node with adventitious roots.