An inbred line (TM‐1) was developed at the Texas Agricutural Experiment Station as a standard reference cotton (Gossypium hirsutum L.) for genetic and cytogenetic experimentation. Its origin and development is described. The results of a performance test of several advanced generations of the inbred were used to characterize the agronomic properties of the line and to evaluate the effects of inbreeding.

Certain features of the gross morphology of the cotton plant furnish clues to earliness of crop production. Three such features — (1) node of first fruiting branch (NFB), (2) number of vegetative branches (NVB), and (3) percentage of bolls on vegetative branches (PBV) — were used as morphological measures of earliness in the studies reported here. All of the morphological measures were significantly correlated but, because of its higher heritability and lower variability, NFB is considered the most reliable and the most practical one of the three. NFB and NVB were signficantly correlated, phenotypically, with product‐quantity measures of earliness. Mean maturity date (MMD), a product‐quantity measure, and NFB, a morphological measure, are separate estimates of the same phenomenon: i.e., earliness of crop maturity. Used together, they are mutually supporting and they form a reliable basis for estimating earliness in genetic studies and breeding programs.

REVIEW OF LITERATURE Extensive studies on the growth pattern of the cotton plant and the characteristics of the different varieties that condition early maturity have been reported by Ewing (3), Martin et al. (8), Harland (5), McNamara et al.

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