COREL! 
Days Main Uses ere Peas 81 
Petits Pois Piselli 
Erbsen PEAS Guisantes 
Pisum sativum 
An interesting aspect of pea seed production is the fight against “rabbit ears.’’ These 
are rogues, or off-types, named for the shape of their leaves, which actually resemble 
rabbit ears. They generally have sparse foliage and small, tight pods. Usually the peas 
are tough, and often they are inedible. Rabbit ears are always present in certain vari- 
eties (such as Hundredfold, Laxton’s Superb, and Thomas Laxton), and if uncon- 
trolled, they will literally run wild, multiplying rapidly and ruining the stock in a few 
generations. 
The only weapons effective against these pests are purelining and rogueing. 
Purelining means making single plant selections, followed by reselection and increase 
under close observation. One might think the controlled increase of seed from a sin- 
gle, ideal plant would eliminate these rogues. But certain varieties seem to have in 
their genetic makeup a tendency to break down—to ‘‘throw” rabbit ears—more mark- 
edly than others. 
Hence purelining must be supplemented by rogueing—removing off-types from the 
commercial seed production fields. This is done by trained crews under the supervision 
of Corneli field men. Rogueng is no fancy frill. It is absolutely essential in the pro- 
duction of good seed. And it accounts for a significant part of the cost, averaging per- 
haps 5% of the wholesale price of the seed. 
Traces of rabbit ears and other types of rogues are found even in the best commercial pea 
seed; but by continuously bringing on new purelines and by rogueing as much and as 
often as needed, Corneli’s plant breeders and production supervisors keep the level of 
these off-types to just a trace. 
SPECIAL TERMS RELATING TO PEAS 
Since peas have become one of the nation’s most important canned and frozen vege- 
tables, we include in these descriptions some data important to processors. Terms 
such as “heat units” and “sieve sizes’? are a part of the everyday language of pea 
packers, and these characteristics are vital in the evaluation of a pea variety. They are 
also of interest to the student or home gardener who is interested in the detailed char- 
acteristics of a variety. Therefore, brief explanations of these terms follow: 
HEAT UNITS’ The prime maturity stage in peas comes and goes rather quickly, espe- 
cially in areas where the peas are likely to be maturing in warm weather. Accordingly, 
it is important for pea processors to be able to forecast rather accurately the date 
on which this prime maturity will be reached. Heat units are one tool used for 
such prediction. They may be expressed either in terms of ‘‘degree days’”’ or “degree 
hours,” and the degree day figure is the one most commonly used. The degree day fig- 
ures included in these descriptions were obtained from replicated test plots at our 
Twin Falls, Idaho breeding farm. They very likely will not be accurate for the same 
variety when grown under other conditions, on different soils, or in other areas. They 
do offer a basis, however, for comparing one variety with another; and they may be 
used as they stand to give the processor an indication of when he should start making 
careful and frequent checks of the fields, for maturity. 
SIEVE SIZES Many processors pass the peas coming in from the fields and the 
viners over sieves of varying sizes, and pack the various diameters separately, since 
fancy grade peas of number two sieve size normally sell for a higher price than fancy 
peas of number three size, and so on. The sieve diameters corresponding to the differ- 
ent sizes are as follows: sieve size number one equals 18/64"; two, 20/64’; three, 
22/64"; four, 24/64’; five, 26/64"; six, 28/64". 
TENDEROMETER This is a device for measuring hardness of peas. A reading of 100 
or less corresponds to “‘fancy.”’ 
STANDARD, EXTRA STANDARD, FANCY These terms refer to hardness, mainly a 
matter of maturity. 
* Asterisks indicate smooth seeded varieties. 
