Subsurface drip (SSD) is used as a water‐efficient alternative to overhead irrigation in many crops. This study compared soil water, water use, crop maturity, lint yield, and fiber quality of cotton (Gossypium hirsutum L.) grown with SSD to cotton grown with overhead irrigation. Three experiments were conducted at two Georgia locations in 2004 and 2005. Treatments consisted of overhead irrigated, nonirrigated, SSD matched to overhead irrigation rates (SSD Matched), and SSD based on soil water (SSD Fed). Cotton maturity was affected by irrigation treatment as nonirrigated cotton matured earliest, whereas overhead irrigated cotton matured latest. Subsurface drip irrigated cotton produced similar or higher lint yields than overhead irrigated cotton. Subsurface drip provided adequate soil water and irrigation amounts were 4.4, 8.2, and 0.5 cm less than overhead irrigation at the three locations. Water use efficiency (WUE) of cotton SSD irrigated was 23 and 15% higher than overhead‐irrigated cotton in two experiments. Irrigation method did not substantially affect fiber quality; however, micronaire was higher in cotton from the SSD Fed treatment than cotton in the Overhead treatment in two locations. We conclude that SSD irrigation provides the same positive effects as overhead irrigation in cotton production while reducing irrigation water use and may allow for improved irrigation efficiency.

The production of fruit on upland cotton (Gossypium hirsutum L.) varies with environment, cultivar, and management practices, including irrigation. Yield increase in response to irrigation is a combination of additional boll production on the plant and differences in the size of individual bolls. Previous research on this subject is incomplete. The purpose of this research was to compare the effects of irrigation on boll distribution and boll size in four cotton cultivars in West Texas. Boll distribution and boll mass in response to 10 daily irrigation levels (0–6.5 mm d−1) were compared among four cultivars with varying maturities [‘Deltapine 1212 B2RF’ (DP1212), ‘Deltapine 1219 B2RF’ (DP1219), ‘FiberMax 2484 B2F’ (FM2484), and ‘FiberMax 2011 GT’ (FM2011)] from 2011 to 2013 in Lubbock, TX. Boll production and retention followed cultivar‐specific patterns in all 3 yr. Two cultivars (DP1212 and FM2011) produced fruit primarily at the bottom and middle of the plant, one had increased production high on the plant (DP1219), and one produced fruit almost exclusively in the middle of the plant (FM2484). Both boll number and boll mass contributed to lint yield, with boll number being the major determinant (on average, 90%) of lint yield, whereas boll mass accounted for 10% of lint yield on average. The contribution of boll number and boll size to yield varied among cultivars and did not appear to be wholly maturity‐related. Research studies focused on boll number should be aware that boll distribution does not account for all of the variation in yield.

The use of high-throughput phenotyping aids breeding programs in making more informed selections and advancements. This study's objectives were to determine which proximal remote sensing parameters (normalized difference red edge [NDRE], normalized difference vegetation index [NDVI], difference between canopy and air temperatures [∆T], and plant height) are robust estimators of cotton lint yield and to use a time-integrated function of one parameter as a single phenotypic measurement for predicting yield. This study evaluated remote sensing parameters (NDRE, NDVI, ∆T, and plant height) measured weekly from squaring through boll production and development. Of these measurements, NDRE was most consistent in terms of r 2 , slope, and normality in predicting yield. From these findings, a temporal analysis was calculated as NDRE integrated over the season, namely NDRE-days. Significant r 2 values were detected for the individual remote sensing measurements, with the largest r 2 occurring around peak bloom (80 d after planting). An r 2 of 0.81 was identified between ∆T and lint yield in 2015, whereas in 2017 the largest r 2 value with lint yield was with NDRE (r 2 = .71). The temporal analysis showed a significant relationship between NDRE-days and lint yield (P < .0001; r 2 = .58 in 2015 and r 2 = .68 in 2017) that was not cultivar specific. This study presents a suitable method that breeders could use to efficiently evaluate plant growth and estimate yield for variety selections while cutting resource requirements.Abbreviations: ∆T, difference between canopy temperature and air temperature; ET, evapotranspiration; FM, FiberMax; GDD 15.6 , 15.6 • C growing degree days; GPS, global positioning system; NDRE, normalized difference red edge; NDVI, normalized difference vegetation index; SDI, subsurface drip irrigation; ST, Stoneville.

This study was designed to determine how within‐boll fiber quality of cotton (Gossypium hirsutum L.) is affected through irrigation, cultivar, and plant density management. Field experiments were conducted in 2006 and 2007 using two contemporary cultivars, arranged in a split‐split plot design with two irrigation rates (6.33 and 4.32 mm d−1) as the main plot, plant density (79,071; 128,490; 197,677 plants ha−1) as the subplot, and cotton cultivar (FM9063B2RF and ST4554B2RF) as the subsubplot. Plants from 3 m of one row from each plot were hand harvested by fruiting position. First fruiting position bolls from main‐stem nodes 9 and 14 were hand harvested by seed position and ginned separately for Advanced Fiber Information System (AFIS) fiber quality analysis. Increased irrigation generally increased fiber length and upper quartile length, and decreased fineness and maturity ratio. Irrigation effects were greater on fiber length and maturity ratio at seed positions close to the apex of the locule. Increased plant density reduced both fineness and maturity ratio. The cultivar FM9063B2RF produced longer, more mature, and finer fibers than the ST4554B2RF. The overall lowest fiber quality (i.e., shorter and less mature fibers) occurred at seed positions close to the apex of the locule. The superior fiber quality (i.e., longer and more mature fibers) was from the middle to the base of the locule. Abundant rainfall diminished the effects of irrigation on fiber quality.

All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher.T he Southern High Plains of Texas, characterized by hot periods that may last from April through October, provides highly favorable conditions for cotton growth and development. However, within this growing period, a relatively low annual average rainfall of 475 mm and a relatively high average potential evapotranspiration of 1000 mm results in water supply being a limiting factor for cotton in this region. Th us, information about how to maximize yield with limited water is needed. Furthermore, planting seed costs are currently higher than in the past due to advances in transgenic technology and the adoption of seed patents. A proper plant density may not only maximize cotton yield and fi ber quality for a given level of available water but may also reduce inputs by reducing excessive plant density. Current research has shown that boll size and boll number per unit land area are readily infl uenced by irrigation rate (Pettigrew, 2001). Additionally, Bednarz et al. (2000) have shown that the number of bolls per plant and size of the bolls were infl uenced by plant density. Worley et al. (1974) indicated that boll number per unit land area was the largest contributor to lint yield, followed by seed number per boll and lint mass per seed. Harrell and Culp (1976) suggested that more seeds per boll may be desirable due to the greater amount of surface area for lint production within the boll. Bridge et al. (1973) reported a general change to smaller bolls, smaller seeds, and higher lint percentage in successful Delta cultivars. Miller and Rawlings (1967) also found that, as yield increased by selection, lint percentage and seeds per boll increased while boll and seed size decreased. Th ese fi ndings illustrate that within-boll yield components have evolved as a result of selection for increased lint yield. Are within-boll yield components infl uenced by irrigation and plant density as well? If so, it should be possible to identify crop management practices that may capitalize on the most basic yield components. Moreover, Bednarz et al. (2006) reported that within-boll yield components diff er among cultivars. Th erefore, it is reasonable to assume that within-locule yield components diff er among cultivars as well. Th e objective of this study was to determine how yield components in two contemporary cotton cultivars were altered through irrigation and plant density management. MATERIALS AND METHODS Cultural PracticesExperiments were conducted in 2006 and 2007 at the Agricultural Complex for Advanced Research and Extension Systems (AG-CARES) facility in Lamesa, TX on an Amarillo fi ne sandy loam (fi ne-loamy, mixed, superactive, thermic Aridic Paleustalfs). All treatments were arranged in a split-split plot design with three replications where irriga...