Fiber length development period (FLDP) is the biological time interval from anthesis to the day that the lint fibers ceased growing in length.
Data reported by Braden and Smith (2004) indicated that TAM 94L-25 and TAM 94M-14 attained their longer average fiber length not only through an extended FLDP for each year, but also from a greater final average daily growth rate when averaged across years.
Phenology measurements, VFIA, VFIB, HFI, BMP, and FLDP were positively associated (P < 0.01) with each other, indicating harmony among the two fruiting interval measurements and as these fruiting intervals increased, so did the BMP and FLDP (Table 3).
FLDP had significant and positive correlations with UQLw and UHM.
FLDP for these seven genotypes was associated with all crop maturity indicators and had the highest correlation with BMP.
Since TAM 94L-25 and TAM 94M-14 produce long or near-extra long HVI fiber lengths, then the logical question is, do they derive this extra length through a greater average daily fiber growth rate, or longer FLDP? Analysis of variance of [L.sub.W] for each DPA revealed significant year effects for the first six DPA, 16, 19, 22, 25, 28, and 31, and genotype x year interaction for 35 and 38 DPA (Table 1).
Although Suregrow 125 [L.sub.W] at 25 DPA, which appears to be an anomaly in the data, and Tamcot CAMD-E [L.sub.W] at 28 DPA were similar to their [L.sub.W] at 31 DPA (Table 2), their maximum numerical average [L.sub.W] was not attained until 31 DPA and thus 31 DPA was considered to be the FLDP for all genotypes in this study.
TAM 94L-25 and TAM 94M-14, with a higher FADGR and longer FLDP, produced longer fibers than Acala Maxxa, which had a shorter FLDP.
These breeding lines attained longer fibers through a greater FADGR coupled with a longer FLDP. TAM 94L-25 and TAM94M-14 also exhibited a more sustained ADGR through 31 DPA than all other genotypes which tended to fluctuate in SADGR.
Abbreviations: ADGR, average daily growth rate; AF1S, advanced fiber information system; DPA, day(s) postanthesis; FADGR, final average daily growth rate; FLDP, fiber length development period; HVI, high volume instrument; [L.sub.W], length by weight; SADGR, segmented average daily growth rate; TAES, Texas Agricultural Experiment Station; UHM, upper half mean.