Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/31/1998
Publication Date: N/A
Technical Abstract: A winter-hardy buffelgrass (Pennisetum ciliare Link. syn Cenchrus ciliaris L.) selection was released as the cultivar 'Frio.' It is significantly more winter hardy than 'Common' buffelgrass, the most widely grown cultivar in south Texas and northern Mexico. Frio buffelgrass is intended to reduce winter damage in areas where buffelgrass is currently grown and to expand the northern and western range of buffelgrass. BIII hybridization, fertilization of an unreduced egg (2n+n), is recognized as a means of improving apomictic plants; however, this phenomenon normally occurs at too low a frequency to be used as a reliable breeding method. An experiment was conducted to determine if the frequency could be increased by early pollination. Different apomictic buffelgrass accessions were pollinated from 0 to 3 days prior to anthesis and the frequency of BIII hybridization was determined for each pollination interval. Early pollination increased the frequency and it appeared also to be influenced by plant genotype. Th highest frequency of BIII hybridization was in excess of 8%. Research to identify and clone the genes controlling apomixis as well as important agronomic traits in buffelgrass is continuing. This effort has taken two different approaches. One, virtual subtraction, is used to isolate pistil specific genes from a pistil cDNA library constructed from an obligate apomictic genotype. cDNA clones from the library are screened by virtual substraction with cDNA probes from other tissues and in situ hybridization analyses is used to identify in what tissues the pistil specific probes are expressed. The second is a map-based cloning approach. A low density buffelgrass map with markers spaced at about 20 cM intervals is being developed using cDNAs and genomic DNAs which have been mapped in sorghum.