Purdue University Agricultural Experiment Station Lafayette, Indiana
Mimeo BP-11-14
March 1959

1958 PERFORMANCE TRIALS OF
SINGLE CROSSES AND EXPERIMENTAL DOUBLE CROSSES

This publication is the first of a series reporting the performance of single-cross predictive trials and experimental double crosses. The performance tests of all experimental double crosses and of single-cross trials away from Lafayette are the responsibility of Paul L. Crane, while the single cross tests at Lafayette are the responsibility of A. M. Brunson and L. R. House.

The early maturing single-cross test, involving all combinations of 18 inbred lines, was grown at the Agronomy Farm, Lafayette, and at Pinney-Purdue Farm, Wanatah. At the Lafayette test a small portion of one replication was not harvested because of water damage.

The late maturing single-cross group, involving all combinations of 25 inbred lines, was grown at the Agronomy Farm, Lafayette, and at the Princeton Farm, Princeton.

EXPERIMENTAL METHODS

Method of Planting. The plots at Wanatah and Princeton were 1 x 16 hills in size. Hill spacings were 40” x 40” with 4 kernels planted in each. At this rate a perfect stand approximates 15,680 plants per acre. At Lafayette the spacing was 20” between hills within each plot and 2 kernels dropped per hill, giving the same total number of plants per acre. No thinning was done and the resulting stand was about 90% at harvest.

Yield. Acre yields are calculated on the basis of shelled grain containing 15.5% moisture, the maximum allowable for No. 2 corn.
Lodging. In the single-cross tests root lodging and stalk breakage percentages were combined. At Wanatah and Princeton these data were recorded in late October, while those at Lafayette were recorded in late November, and were from an extra replication allowed to stand without picking until good differentials were evident. Lodging data for the experimental double crosses were recorded immediately before harvest and show stalk breaking and root dodging separately.

Silking Date. The silking date gives the number of days from planting Mil one-half of the plants were in silk.

Ear and Plant Heights. The first ten plants of each plot were measured in inches and averaged.
Stalk Rot. Ten plants in each plot of a separate block of the early sin-gle crosses were inoculated with Diplodia zeae. Grades are reported from 0 Resistant) to 5 (susceptible).

Grading. To evaluate these single crosses as possible seed parents in double-cross hybrids, the seed harvested from each, was graded. Tables 1 and Report the percentages by weight of the 24/22 and 22/18 flats which passed through a 13/64 slotted screen.