Date of Award

1-1970

Document Type

Thesis

Abstract

A Study was conducted to determine the association between yield of sugar per acre and its components as well as associations among the components for 76 randomly chosen sugarcane clones (Saccharum sp.) derived from the cross C.P. 48-103 X C.P.33-224. The parental clones and two varieties, C.P.44-101 and C.P.52-68, were grown as checks.

Data were taken from a replicated yield trial representing one year only of the plant cane crop. The traits measured involved yield of sugar per acre, yield of cane per acre, yield of sugar per ton of cane, stalks per acre, mean weight per stalk, mean length per stalk, mean diameter per stalk, sucrose percent, brix, purity of juice, and percent fiber in cane. The data were used to calculate phenotypic and genotypic correlation coefficients.

Both yield of cane per acre and sugar per ton of cane were highly associated with yield of sugar per acre. Thus, rigid selection should be practiced for both components beginning as early as possible.

Moderate, positive associations were found between yield of cane per acre and three of its components: number of stalks per acre, weight per stalk, and length per stalk. A significant, but low, association occurred with diameter per stalk, it appeared that selection for high stalk population and tallness would prove roost effective in obtaining clones with high yielding capacity.

Strong positive associations were found between sugar per ton of cane and both sucrose percent and brix. Thus, effective selection can be practiced early in a breeding program for high sugar per ton of cane by utilizing sucrose percent and/or brix.

Several important associations occurred between the yield components which would have significance in sugarcane breeding, one was a moderate negative association between number of millable stalks per acre and stalk diameter. Selection for exceptionally large stalk diameter would tend to eliminate desirable clones with above average stalk population.

Both length per stalk and sucrose percent showed a low, positive association with fiber percent, which may cause serious problems unless clones are eliminated early in the breeding program on the basis of high fiber.

A moderate negative correlation was found between stalk diameter and percent fiber. Thus, the apparently desirable practice of retaining clones which are average or below in stalk diameter — comparable to C, P.52-63 r- would tend to raise the fiber content of selected clones unless the clones are also screened to eliminate those unacceptably high in fiber.

There was, as expected, a strong association between sucrose percent and brix which emphasizes the importance of selecting for high brix levels in material before sucrose percent can be measured, such as in the single stool stage.

Of special significance was the absence of negative associations between yield of cane per acre and sugar per ton of cane or sucrose percent, it appears that no serious complication exists to combining high cane yield with high sucrose content.

DOI

10.31390/gradschool_disstheses.8376

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