HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Balota, M. Articles by Lazar, M. D. Search for Related Content PubMed Articles by Balota, M. Articles by Lazar, M. D. Agricola Articles by Balota, M. Articles by Lazar, M. D. Related Collections Crop Physiology & Metabolism Wheat Field evaluation techniques

Canopy Temperature Depression Sampling to Assess Grain Yield and Genotypic Differentiation in Winter Wheat

^a Texas Agricultural Experiment Station, 2301 Experiment Station Rd, Bushland, TX 79012
^b USDA-ARS Conservation and Production Research Lab., Bushland, TX. Mention of a trade name or product does not constitute endorsement to the exclusion of other products that may be also suitable

View larger version (20K): [in this window] [in a new window]   Figure 1. Diurnal canopy temperature depression (CTD) trends for three closely related wheat (Triticum aestivum L.) lines grown under (A–C) dryland and (D–E) irrigated conditions during 3 yr at Bushland, TX. Points represent hourly means during the entire measurement period, which was from heading to –20 d after anthesis in 2000 and from heading to –40 d after anthesis in 2001 and 2002. See Fig. 3 for error bars for graphs A to C. Vertical bars in graphs D and E represent ± 1 SD. Genotype TX86A5606 was the most drought sensitive and TX86A8072 was the most drought tolerant (Lazar et al., 1995).

View larger version (20K): [in this window] [in a new window]   Figure 2. Genotypic effect on canopy temperature depression (CTD) at midday and at predawn for winter wheat (Triticum aestivum L.) under dryland conditions. Points represent mean values for the entire measurement period. Vertical bars represent ±1 SD. Genotype TX86A5606 was most drought sensitive and TX86A8072 was most drought tolerant (Lazar et al., 1995).

View larger version (22K): [in this window] [in a new window]   Figure 3. The relations between seasonal mean canopy temperature depression (CTD) at 1200 h and winter wheat (Triticum aestivum L.) grain yield for individual plots under (A) dryland conditions in 2000, 2001, and 2002 at Bushland, TX (P < 0.01, 0.01, and 0.20, respectively), and (B) irrigated conditions in 2001 and 2002 at Bushland, TX (in 2001, P < 0.025; in 2002, correlation was not significant; without TX86A5606 in 2002, P < 0.0001).

View larger version (23K): [in this window] [in a new window]   Figure 4. Correlation of wheat (Triticum aestivum L.) grain yield with canopy temperature depression (CTD) at 1200 h at 2 wk after anthesis in (A–B) 2000 and (C–F) 2001, using days of the year (DOY) with contrasting solar irradiance, vapor pressure deficit, and wind speed (Table 4). In 2000, DOY 131 was 11 May; on DOY 133, solar irradiance at 1200 h was 750 W m–2 and daylight average between 0700 and 1900 h was 450 W m–2: (A) including CTD data from DOY 133 gave a linear model with r2 = 0.17 and standard error of the estimate (SEE) = 29; (B) excluding CTD data from DOY 133 gave a linear model with r2 = 0.48 and SEE = 23. In 2001, DOY 132 was 12 May: (C) using data from all 7 d, the model r2 = 0.04 and SEE = 38; (D) without DOY 132, when solar irradiance at 1200 h was 230 W m–2 (Table 4), r2 = 0.34 and SEE = 33; (E) without DOY 132 and DOY 133, when wind speed at 1200 h was 5 m s–1, r2 = 0.41 and SEE = 31; and (F) without DOY 132, 133, and 134, r2 = 0.57 and SEE = 27. On DOY 134, wind speed at 1200 h was 7 m s–1.

View larger version (10K): [in this window] [in a new window]   Figure 5. Correlation of canopy temperature depression (CTD) measured at 0700 h and wheat (Triticum aestivum L.) grain yield under dryland conditions in 2001. Day of the year (DOY) 123 was 3 May; on DOY 124 at 0700 h, a rain event of 6 mm occurred: (A) using data from both days, r2 = 0.19; (B) without data from DOY 124, r2 = 0.66.

View larger version (18K): [in this window] [in a new window]   Figure 6. Correlations of canopy temperature depression (CTD) at 1200 h measured at preheading and wheat (Triticum aestivum L.) grain yield under dryland conditions in 2002. Day of the year (DOY) 105 was 15 April. Data were taken on days with contrasting weather in terms of solar irradiance, vapor pressure deficit, and wind speed (Table 4). For individual days, r2 = 0.57 on DOY 105, 0.64 on DOY 106, 0.52 on DOY 107, 0.58 on DOY 108 and 0.57 on DOY 109. When all data are combined, r2 = 0.03.

View larger version (22K): [in this window] [in a new window]   Figure 7. An example of cluster analysis for canopy temperature depression (CTD) sampling in wheat (Triticum aestivum L.). Data represent hourly mean CTD during anthesis (left) and 2 wk from anthesis (right) from all years combined. Clusters are hours from 0 to 0800, 0900 to 1800, and 1900 to 2300 h. Similar clusters were obtained when individual years and stages were used.

View larger version (16K): [in this window] [in a new window]   Figure 8. Regression tree model for wheat (Triticum aestivum L.) yield using canopy temperature depression (CTD) data at anthesis as the independent variable in 2001 (left) and comparison of measured yields with regression tree models (right). The solid line represents the regression line for TX86A8072 (slope = 0.67, standard error of the slope [SES] = 0.2); the dotted line for TX86A5606 (slope = 1.15, SES = 0.2); and the dashed line for TX88A6880 (slope = 0.95, SES = 0.4); gy = grain yield (g m–2), SEE = standard error of the estimate, and PRE = proportion of reduction in error.

View larger version (16K): [in this window] [in a new window]   Figure 9. Regression tree model of wheat (Triticum aestivum L.) yield with canopy temperature depression (CTD) data measured at anthesis as the independent variable in 2002 (left) and comparison of measured yield with regression tree models (right). The solid line represents the regression line for TX86A8072 (slope = 0.82, standard error of the slope [SES] = 0.12); the dotted line for TX86A5606 (slope = 1.02, SES = 0.16); and the short dashed line for TX88A6880 (slope = 1.16, SES = 0.16) ; gy = grain yield (g m–2), SEE = standard error of the estimate, and PRE = proportion of reduction in error.