Dj. Wolyn, ESTIMATES OF MARKETABLE YIELD IN ASPARAGUS USING FERN VIGOR INDEX ANDA MINIMUM NUMBER OF DAILY HARVEST RECORDS, Journal of the American Society for Horticultural Science, 118(5), 1993, pp. 558-561
Fern vigor indices and estimates of percent marketable yield (PMY) wer
e used to determine alternative measures of asparagus (Asparagus offic
inalis L.) marketable yield. Total yield was highly correlated (0.75 l
ess-than-or-equal-to r less-than-or-equal-to 0.91), and marketable yie
ld was not correlated with fern vigor indices. The products of fern vi
gor indices and seasonal PMYs were highly predictive of marketable yie
ld (r greater-than-or-equal-to 0.95). When the products of each daily
PMY estimate and fern vigor index for the same season were determined,
then averaged over years, <30% of correlations with marketable yield
were less-than-or-equal-to 0.90, and r values varied considerably duri
ng the season. The products, averaged for 2 years, of fern vigor index
and mean PMY estimated from combinations of three harvest dates durin
g the season, except from the first harvest week, were associated with
marketable yield. For the 40 3-day average estimates of PMY examined,
95 % of Pearson correlation coefficients were greater-than-or-equal-t
o 0.90 and all were greater-than-or-equal-to 0.88. Thus, fern vigor in
dex and PMY estimates from three harvest dates may be used to predict
temperate zone marketable yield, decreasing labor requirements for yie
ld trials, and facilitating evaluation of many experimental hybrids.