DESCRIPTORS FOR PECAN
Phenology of vegetative growth
Bud growth (rated 1=dormant, 2=swell, 3=inner scale split, 4=burst, 5=first leaflet expansion, 6=25% expansion, 7=to 50% leaf expansion, 8=to 75% leaf expansion, 9= fully expanded leaves (See Budbrk.doc in Manual)
Leaf drop (rate as percent of leaves remaining, or use scale of 1=dormant, 2= to 25% remaining, 3= to 50% remaining, 4= to 75% remaining, 5= over 75% remaining.)
Leaf condition on date (0=defoliated, 1= senescent, 2=mature, 3= immature, 4= active growth)(Defoliation date is often useless, since all defoliate at first freeze some years)
Cold hardiness- Need objective methods (e.g. differential thermal analysis, electrolyte leakage).
Trunk diameter (measured at uniform height (2cm in greenhouse, 1 ft for young seedlings in the field, at 3 ft for grafted trees in orchard, dbh for native trees). For small trees, diameter is measured with calipers. For large trees, diameter is recorded using calibrated circumference tape during dormant season.
Tree height/canopy width (measured in dormant season with clinometer; canopy width measured across widest point in axis of row).
Leader type (methods needed)
Shoot characteristics (methods needed)
Secondary growth (+ or -, noted in August, or appropriate date of record)
Leaf color (rate on 1-10 from dark green to brown, based on Munsell Color Chart for Plant Tissue; see lfcolor.doc in Manual
Nutrient uptake based on foliar analysis (mid-leaflet pair of mid-leaf from mid-shoot of current seasons growth in sun, sampled in July)
Disease and pest resistance
Pecan scab [Fusicladosporium effusum (Partridge & Morgan-Jones], rate in June and August for nuts, leaves (lamina only) using Hunter-Roberts scale (Pecan Quarterly 12(3):3-6) (see lfscab.doc and nutscab.doc in Manual)
Vein spot (Gnomonia nerviseda Cole) rate on basis of lesions on rachis (not lamina) where 1=0 lesions, 2=1-5 lesions, 3=6-10 lesions, 4=>10 lesions.
Downy spot (Mycosphaerella caryigena Demaree and Cole)
Pecan nut casebearer (Acrobasis nuxvorella Neunzig)
Hickory shuckworm (Cydia caryana Fitch)
Pecan weevil (Curculio caryae Horn)
Yellow aphid complex
Black pecan aphid
Flowering and yield characteristics.
Dichogamy (record first and last dates of pollen shed and pistil receptivity and calculate early, mid or late season pollen shed, pistillate receptivity)(Pollen adherence is the best criterion of receptivity)
Nuts per cluster (mean of at least 10 clusters, counted in September)(see harvphen.html in Manual)
Percent terminals with clusters (count 50 terminal branches around the canopy in September, and express the number with fruiting clusters as a percentage of total) )(see harvphen.html in Manual)
Nut development phenology
Cotyledon size (longitudinal cut, 1=1/4 extended, 2=1/2 extended, 3=3/4 extended; 4 to base)
Cotyledon development (longitudinal cut, 1=water 2=gel (+water), 3=dough (-water)
Shell hardening (radial cut at tip, middle and base of nut, perpendicular to suture)(see hardening.html in Manual)
Shuck dehiscence (date of 75% split (valves separated to allow visibility of the nut)
Harvest season (actual date of harvest)
Individual tree yield (weight of sound, marketable nuts)
Nut quality characteristics (based on 15 nut samples taken at harvest, with 10 being destructively measured, and 5 being used as voucher)
Nut length, width, and height (see nutmeas.html in Manual)
Nut shape (derived from length to height ratios)(see notes in Cultivar Index)
Nut weight in grams (calculate number of nuts per pound)
Nut volume (determined from buoyancy)
Kernel weight in grams (calculate percent kernel)
Suture (note integrity)
Kernel color rated on 1-6 scale (Thompson, Grauke and Young, J. Amer. Soc. Hort. Sci. 121(3):548-553. 1996.)