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United States Department of Agriculture

Agricultural Research Service

Research Project: MOLECULAR AND GENETIC ENHANCEMENT OF ABIOTIC STRESS TOLERANCE IN SORGHUM Title: Developmental and genetic analysis of a short leaf mutant, a key resource for plant architecture modification in sorghum

Authors
item Burow, Gloria
item Burke, John
item Xin, Zhanguo

Submitted to: Journal of Plant Growth Regulation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 21, 2013
Publication Date: June 8, 2013
Citation: Burow, G.B., Burke, J.J., Xin, Z. 2013. Developmental and genetic analysis of a short leaf mutant, a key resource for plant architecture modification in sorghum. Journal of Plant Growth Regulation. 71:271-280.

Interpretive Summary: Changes in overall plant configuration and forms known as plant architecture have been demonstrated as one of the major contributing factors that ushered in the Green Revolution resulting in achieving significant increases in grain yield for wheat and rice. For sorghum (Sorghum bicolor L. Moench.), possible changes in plant architecture is an important trait that deserves further attention and could positively affect yield parallel to rice, wheat and corn. Here we report the characteristics of a genetic stock of sorghum which can be used as a starting germplasm or material for breeding changesinto sorghum plants’ overall configuration and form. This genetic stock is a mutant which prominently displays short and erect leaves. These leaf characteristics gives sorghum a very compact appearance to the canopy configuration. These modified could make sorghum more adapted to large increases in number of plants planted per unit area. In summary , the short leaf mutant of sorghum described here could be a vital resource in understanding how to manipulate plant canopy architecture to allow more efficient solar interception/utilization throughout the canopy in conjunction with high planting density, and as an effective tool in mitigating shade avoidance effect.

Technical Abstract: Modification in plant architecture have been demonstrated as one of the major contributing factors that ushered in the Green Revolution resulting in achieving dramatic increases in grain yield for wheat and rice. For sorghum (Sorghum bicolor L. Moench.), possible alteration in plant architecture is an important trait that deserves further attention and could positively affect yield parallel to rice, wheat and corn. Here we report the developmental, morpho-physiological and genetic characterization of a sorghum genetic stock, KFS2061, a stable mutant (in the Western Black Hull Kafir background) which distinctly exhibit short and erect leaves which leads to a compact plant architecture. The expression of the short erect leaf trait commenced with the 3rd leaf and is propagated on through the entire leaf hierarchy of the canopy. Further analysis of morphological features indicated that the short leaf mutant exhibited consistent steep leaf angle, 43º from the main culm as vertical reference throughout the plant canopy and distinct thicker leaves with higher specific leaf weight than wild type. Biochemical analysis indicated that this mutant has significantly higher chlorophyll and cellulose content per unit area (cm2) leaf area than wild type. Histological studies revealed significant reduction in cell length along the longitudinal axis and enlargement of bulliform cells in the adaxial surface of the leaf. KFS 2061 also exhibited significant increase in stomatal density. Comparison of agronomic traits between mutant and its wild type progenitor indicated that the mutation could have pleiotropic effects. An analysis of a F2 population derived from the cross between BTx623 and KFS 2061 showed that the mutation is recessive and appeared to be controlled by a single gene. This short leaf mutant is a vital resource in understanding how to manipulate plant canopy architecture of sorghum to allow more efficient solar interception/utilization throughout the canopy in conjunction with high planting density, and as an effective tool in mitigating shade avoidance effect.

Last Modified: 12/26/2014
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