RESPONSE OF TEN COTTON VARIETIES TO VERTICILLIUM WILT IN THE NORTHERN ROLLING PLAINS J. E.

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1 RESPONSE OF TEN OTTON VRIETIES TO VERTIILLIUM WILT IN THE NORTHERN ROLLING PLINS J. E. Woowar Texas &M grilife Extension Service Texas Tech University Luock, TX J. H. Ramirez Texas &M grilife Extension Service Vernon, TX G.. Morgan Texas &M grilife Extension Service ollege Station, TX T.. Wheeler Texas &M grilife Research Luock, TX L.. Haynes Texas &M grilife Extension Service larenon, TX Introuction Verticillium wilt, cause y the soilorne fungus Verticillium ahliae Kle., is an economically important isease of cotton (Gossypium hirsutum L.) throughout the High Plains of Texas. Recent oservations inicate that the isease is ecoming more prevalent in areas of the Rolling Plains. urrently, management of Verticillium wilt is limite to the use of partially resistant varieties; however, little information on the performance of cotton varieties in fiels infeste with V. ahliae in the Rolling Plains are availale. In aition, potassium eficiency symptoms are routinely oserve towars the later part of the growing season in this region an such conitions are known to affect Verticillium wilt. The occurrence of potassium eficiency symptoms has een more common where proucers are attempting to maximize yiel uner rought conitions (personal oservation). The initial ojective of this stuy was to evaluate the performance of cotton varieties in a fiel infeste with V. ahliae; however, the opportunity arose to etermine the effect of potassium eficiency-like symptoms on lint yiel in presence of the isease. Materials an Methos The trial was conucte in in rmstrong o. Texas ( , ). Treatments consiste of the cotton varieties ll-tex NitroB2RF, eltapine 0912B2RF, eltapine 1321B2RF, FierMax 2011GT, FierMax 2484B2F, FierMax 2989GLB2, NexGen 3348B2RF, NexGen 4012B2RF, Phytogen 367WRF an Phytogen 499WRF. See were plante at a rate of 3.2 see per foot (on 30 in row spacing) into an marillo fine sany loam on pril 28, Plots were six rows wie an spanne the length of the fiel (~1250 feet). Treatments were arrange in a ranomize complete lock esign with three replications. ll management practices were at the iscretion of the collaorating proucer. The evelopment of Verticillium wilt (Fig. 1a) was assesse throughout the growing season. Leaf samples were collecte y the proucer throughout the growing season an sumitte to a commercial laoratory for nutrient analysis. Severe potassium eficiency-like symptoms (Fig. 1) were oserve throughout the region uring the latter part of the growing season. erial images were collecte in late ugust an NVI was use to access vegetative growth. eficiency-like symptoms were more severe on the western half of the fiel (Fig. 2); therefore plots were ivie in half an harveste separately on Octoer 31 an Novemer 1. Bur cotton weights were estimate using a stationary weigh trailer equippe with igital loa cells. Su-samples were collecte from each plot, ginne an sent to the Texas Tech University Fier an Biopolymer Research Institute for quality analysis. HVI ata were use to etermine ommon reit orporation () loan values, which were use to calculate gross value per acre (which took into consieration all appropriate see an technology fees). ue to the appearance of the potassium eficiency-like symptoms, ata were analyse in a split-plot manner, where crop conition (healthy or unhealthy) serve as the whole plot an variety serve as the su-plot. Means were sujecte to analysis of variance an separate using Fisher s Protecte Least Significant ifferences test (P 0.05). Soil samples were collecte from each plot following harvest an analyse for macronutrients at a commercial laoratory.

Noticeale ifferences in Verticillium wilt incience (Fig. 1a) were oserve in July among varieties ranging 5.3 to 19.3% (Fig. 3).

2 Figure 1. Verticillium wilt (top) an potassium eficiency-like (ottom) symptoms on cotton leaves from the Northern Rolling Plains. Results an iscussion ool soil temperatures were experience (ata not shown) for prior to emergence an may have contriute to ifferences in final plant populations (Tale 1). Noticeale ifferences in Verticillium wilt incience (Fig. 1a) were oserve in July among varieties ranging 5.3 to 19.3% (Fig. 3). isease incience was highest for NexGen 3348B2RF, Phytogen 499WRF an eltapine 0912B2RF, an lowest for NexGen 4012B2RF, FierMax 2989GLB2 an FierMax 2484B2F. There was a sustantial increase in isease incience through early Septemer (ata not shown); however, potassium eficiency-like symptoms (Fig. 1) confoune susequent ratings. eficiency-like symptoms were more pronounce on the north-western half of the fiel (Fig. 2). Results from in-season leaf sampling showe a epletion of potassium from mi-jun through late ug (Fig. 4). Plots were ivie in half to compare the effect of the isorer on lint yiel. Turnouts i not iffer among varieties averaging 29.8% (ata not shown). significant variety potassium status interaction was oserve; therefore, yiels for each variety were presente inepenently etween the two areas (Fig. 5). Overall, yiels were highest for FierMax 2484B2F in oth the eficient an healthy areas averaging 2,202 an 1,881 l ac -1, respectively. Yiels for NexGen 4012B2RF, FierMax 2989GLB2, ll-tex Nitro B2RF an FierMax 2011GT were 553, 319, 272 an 399 l ac -1, respectively. Yiels etween the two areas i not iffer for eltapine 0912B2RF, Phytogen 367WRF, eltapine 1321B2RF an Phytogen 499WRF averaging 1,353, 1,281, 1,239 an 1,199 l ac -1, respectively. ifferences among varieties were oserve for miconaire, length an strength (Tale 1). Leaf grae values were consieraly high for ll-tex Nitro B2RF, NexGen 3348B2RF an Phytogen 499WRF (ata not shown), resulting in euctions that greatly affecte loan value (Tale 1). Gross returns were greatest for FierMax 2484B2F ($1,082 ac -1 ) an lowest for eltapine 1321B2RF, Phytogen 499WRF an Phytogen 367WRF ($597-$599 ac -1 ). Preliminary results of from soil nutrient analysis o not suggest any macro nutrients (incluing potassium) are limite (ata not shown); however, this oes explain the appearance of eficiency-like symptoms that were oserve in the fiel. Results from this stuy suggest that varieties respon ifferently to Verticillium wilt in the Northern Rolling Plains; however, aitional stuies examining the interactive effect of potassium eficiency-like symptoms on variety performance are neee.

North Figure 2. Near infrare aerial image of Verticillium wilt trial, illustrating varietal ifferences an potassium eficiency-like symptoms that evelope on the western half of the fiel. Tale 1.

3 North Figure 2. Near infrare aerial image of Verticillium wilt trial, illustrating varietal ifferences an potassium eficiency-like symptoms that evelope on the western half of the fiel. Tale 1. Final plant populations, fier quality parameters, loan value an net return for ten cotton varieties grown in the Northern Rolling Plains Stan Mic Length Strength Loan value Gross value Variety (plants ft -1 ) (units) (in.) (g tex -1 ) ($ l -1 ) ($ acre -1 ) ll-tex NitroB2RF 2.35 a 3.02 a 1.21 a 31.2 a c eltapine 0912B2RF 1.95 c 3.17 a 1.10 e 29.9 e e eltapine 1321B2RF 2.08 c 2.90 c e FierMax 2011GT 2.27 a 3.18 a 1.14 c a- 817 c FierMax 2484B2F 2.68 a 3.12 a 1.21 a a 1,082 a FierMax 2989GLB c 3.22 a 1.13 c 29.2 e a-c 901 NexGen 3348B2RF a 1.14 c c 618 NexGen 4012B2RF 2.00 c 3.22 a a a 867 c Phytogen 367WRF 1.65 c 2.70 c a-c e Phytogen 499WRF 2.35 a 3.20 a 1.13 c 30.3 c a- 598 e LS (0.05) Means within a column are not ifferent accoring to Fisher s Protecte LS. ata were poole across healthy areas an those exhiiting potassium-like eficiency symptoms (n=6).

4 Total K NexGen 3348B2RF Phytogen 499WRF eltapine 0912B2RF eltapine 1321B2RF FierMax 2011GT Phytogen 367WRF ll-tex NitroB2RF FierMax 2484B2F FierMax 2989GLB2 NexGen 4012B2RF B- B- - B - isease incience (%) Figure 3. Early season Verticillium wilt incience. Bars with the same letter are not ifferent (n=3) accoring to Fisher s Protecte LS (P 0.05). ata were only collecte from areas not exhiiting potassium eficiency-like symptoms y = x R² = Figure 4. Status of total foliar potassium over the 2013 growing season. Re an lack triangles represent Fiermax 2484B2F an Fiermax 2989GLB2, respectively.

5 a Unhealthy B B E c E Healthy e E E E e 0 Figure 5. Lint yiel of cotton varieties affecte y Verticillium wilt an potassium-like eficiency symptoms (unhealthy). Black ars with the same upper case an re ars with the same lower case letters are not ifferent (P 0.05).

2008 COTTON VARIETY PERFORMANCE UNDER VERTICILLIUM WILT PRESSURE

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