Monday, October 28, 2013

Nut development: 28 Oct. 2013

   Each time I checked the development of Maramec nuts this summer, I wondered if they would have enough time to split shuck before the first killing freeze. Well, I got my answer today. I found the shucks split open on our scab-covered Maramec nuts (photo at right).
   Splitting shuck before the first freeze is important but  remember, Maramec was having a hard time filling out its kernel ever since mid-September.  So I collected a few Maramec nuts to check kernel quality. Since scab was also an issue with Maramec this year, I harvested nuts with varying amount of scab infection on the shucks.
     The photo above shows four Maramec nuts arranged by severity of scab infection. Below each nut is a photo of that same nut in cross section. Nut "A" had the least amount of scab and achieved normal size for a Maramec. A look inside nut "A" reveals less than perfect kernel fill with air pockets both within the kernel and near the inner-shell partition. The poor kernel fill observed inside nut "A" was a result of this cultivar running out of time and heat to fill the seed. In this case, scab infection was not severe enough to negatively affect kernel fill.
     Nut "B" is about the same size as nut "A" but total disease coverage on the shuck of nut "B" has caused even poorer kernel fill.  The earlier in the year scab covers the shuck, the greater effect the disease has on nut size.  Nuts "C" and "D" are examples of the how nut size can be affected by scab. Early scab infection had the greatest impact on nut "D" decreasing size and severely limiting kernel fill.