Bl (Broadleaf), a genetic trait that may enhance yields by contributing to the canopy
--Galinat, WC

As an alternative to increasing yield per acre and solar energy capture by denser stands, attempts have been made to use canopy enhancement per plant at lower densities to increase yield. The dominant leafy gene (Lfy) suggested by Shaver increases the number of leaves above the ear from the normal of about 5 to 9 in Lfy. It has been widely tested and does not appear to always increase yield, at the densities tested.

The answer to both canopy enhancement and diversity supplementation may lie in the transfer of quantitative traits. The Bl (broad leaf) trait is one such complex factor that involves a cluster of genes representing the software regulating the course of sequential development during the flow of space-time. It may have significant value in canopy and yield enhancement per plant and possibly also in yield per acre, even at high density. It was discovered in some Choclero maize received from Victor Alamos Sr. of Jacques Seed Co., Santiago, Chile. Choclero is similar to the old Gourd Seed variety of the southeastern United States. Both have an umbrella canopy of wide leaf blades and broad husks enclosing a broad ear bearing 20 rows of shrunken kernels. The broad husks have added value as humita wrappers in Chile. Their counterparts in Mexico serve as tamale wrappers. More importantly the broad husks are associated on the same plant with broad leaf blades, although broad husks may have reduced blades, and leaves may have reduced sheaths and broad blades. This independence of sheath and blade appears to be due to regulation of targeting during development comparable to that of phase change from vegetative to floral. If the potential for fat meristem extends through the vegetative and floral phases, programming may extend the broadness to the floral bracts and to the carpels of the pericarp, resulting in wide kernels.

This developmental linkage must have evolved by means of fat enhancement in meristem size evolving from primitive levels of skinniness in teosinte, the wild ancestor. Teosinte has small (skinny) apical meristems, narrow leaf sheaths and blades, all developmentally linked together with slender two-ranked ears bearing tiny kernels. 


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