rgf1, a mutation reducing grain filling in maize through effects on basal endosperm and pedicel development†

• DOI: 10.1046/j.1365-313x.2000.00747.x
• Publication Date: 2003-03-12T22:00:53Z
• Authors: Monika Maitz; Geraldina Santandrea; Zhiyong Zhang; Shailesh Lal; L. Curtis Hannah; Francesco Salamini; Richard D. Thompson
• Keywords: Pedicel; Caryopsis; Wild type

Summary The maize cob presents an excellent opportunity to screen visually for mutations affecting assimilate partitioning in the developing kernel. We have identified a defective kernel mutant termed rgf1 , reduced grain filling with final weight 30% of wild type. In contrast most endosperm mutants, shows gene dosage‐dependent expression endosperm. kernels possess small incompletely papery pericarp, but embryo development is unaffected and seeds are viable. mutation conditions pedicel greatly reduces transfer layer‐specific markers. exhibits striking morphological similarities mn1 mutant, maps locus approximately 4 c m away from on chromosome 2 maize. Despite starch accumulation no obvious lesion biosynthesis has been detected. Free sugar levels unaltered Rates uptake, measured over short (8 h) periods cultured kernels, increased compared wild‐type excised at 5 DAP vitro also develop differently response variations regime: glucose concentrations above 1% arrest placentochalazal effect kernels. These findings suggest that either uptake or perception sugar(s) cells 5–10 determines phenotype.