Screening cotton genotypes for seedling drought tolerance

Abstract

The objectives of this study were to adapt a screening method previously used to assess seedling drought tolerance in cereals for use in cotton (Gossypium hirsutum L.) and to identify tolerant accessions among a wide range of genotypes. Ninety genotypes were screened in seven growth chamber experiments. Fifteen-day-old seedlings were subjected to four 4-day drought cycles, and plant survival was evaluated after each cycle. Three cycles are probably the minimum required in cotton work. Significant differences (at the 0.05 level or lower) among entries were obtained in four of the seven experiments. A "confirmation test" with entries previously evaluated as "tolerant" (high survival) and "susceptible" (low survival) was run. A number of entries duplicated their earlier performance, but others did not, which indicates the need to reevaluate selections. Germplasms considered tolerant included: `IAC-13-1', `IAC-RM4-SM5', `Minas Sertaneja', `Acala 1517E-1' and `4521'. In general, the technique is simple, though time-consuming, with practical value for screening a large number of genotypes. Results from the screening tests generally agreed with field information. The screening procedure is suitable to select tolerant accessions from among a large number of entries in germplasm collections as a preliminary step in breeding for drought tolerance. This research also demonstrated the need to characterize the internal lack of uniformity in growth chambers to allow for adequate designs of experiments.

Salinity Stress in Arid and Semi-Arid Climates: Effects and Management in Field Crops

“…Cotton is mostly grown in arid and semi-arid regions of the world, where water shortage is a dominant factor [80]. In general, salinity severely hinders cotton growth and development, including the reduced plant height, fresh and dry weights of shoot and roots, leaf area index, node number, canopy development, photosynthesis, transpiration rate, stomatal conductance, yield, fiber quality, and root development [81].…”

Development of a Screening Method for Drought Tolerance in Cotton Seedlings

“…The SDT protocol was developed as a new method for the selection of drought tolerant individual plants among various genotypes subjected to sequential drought cycles. It followed the lead of the research performed by Penna et al (1998) There are some important differences between this protocol and previous soil filled tray methods. Individual plants were evaluated in cone‐tainers to alleviate the competition between plants when they share a common soil volume.…”

“…Fifteen‐day‐old cotton seedlings were subjected to four, 4‐d drought cycles in a growth chamber to determine drought tolerance (Penna et al, 1998). The authors used soil‐filled trays (50 by 35 by 9 cm) containing 12 rows of plants with 12 plants per row.…”

Plant Responses to Salt Stress

“…35% of world fiber usage provided by cotton. Cotton cultivation and production is mostly done in arid and semi-arid regions [48]. Salinity causes negative effects on leaf area affected by osmotic stress, plant growth, root and shoot growth, in addition to these effects salinity causes decreases in photosynthetic activity, fiber quality, metabolic activities [49].…”