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Culm Strength: Key Trait to Identify Lodging Tolerant Genotypes in Pearl Millet

OAR@ICRISAT

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Relation http://oar.icrisat.org/11687/
 
Title Culm Strength: Key Trait to Identify Lodging Tolerant
Genotypes in Pearl Millet
 
Creator Gupta, S K
Shaikh, C G
Ponnaiah, G
Kalleshappa, C C
Kholova, J
Jayalekha, A K
Verma, Y S
 
Subject Plant Breeding
Pearl Millet
Crop Physiology
Genetics and Genomics
 
Description Pearl millet hybrids are cultivated on about 6 m ha area in India. These hybrids are cultivated
primarily in better endowed environments in rainy season or under irrigated environments in summer season,
which experiences high velocity winds coupled with rains around crop maturity stage, leading some of them to
lodge at grain filling/maturity stage resulting into severe yield losses to millet growers. Lodging tolerance (LT) is
a complex genetic trait, determined by various morpho-physiological traits, and there is no standard screening
protocol available to select for lodging tolerance. The selection criterion currently followed by breeders to
identify LT genotypes is highly dependent on weather conditions which are highly unpredictable across years.
Hence, this study was designed to identify some weather-independent and easily-scorable alternative traits to
help breeders select for lodging susceptible/tolerant genotypes in pearl millet. In rainy season of 2016, we
evaluated 3 known lodging susceptible and 4 lodging tolerant hybrids (based on the feedback from seed industry)
for LT linked ten morpho-physiological (shoot and root) traits. Based on results, two traits: culm strength
(measured using digital plant stem strength meter: Model YVD-18) and plant height per stem weight exhibited
significant differences between lodging tolerant and susceptible hybrids, when measured at pre-harvest stage
(milky grain stage) and also at crop maturity/harvesting stage. Mean value of culm strength of susceptible
genotypes was 260 kPa, whereas lodging tolerant hybrids exhibited mean culm strength of 313 kPa. Culm
strength showed positive correlation with crown root angle (r= 0.72) which indicated that wider root spread
angle was directly correlated to lodging tolerance. In summer season of 2017, again 4 susceptible and 3 tolerant
hybrids were evaluated across two environments: well-watered and water stress (no irrigation after grain set)
conditions. Under well-watered environment, tolerant hybrids again showed significantly higher average value
of plant culm strength than susceptible hybrids. Also, significant differences were observed for culm strength
under well-watered conditions for tolerant and susceptible hybrids, while non-significant differences were
observed for culm strength under water stress environments. These two year (2016-17) results indicated that
well-watered conditions are optimal environment for evaluation of pearl millet genotypes/hybrids for lodging
tolerance, and culm strength can be used as a proxy trait for selecting lodging tolerant genotypes.
Further, to validate our results, 13 hybrids were evaluated (4 susceptible and 9 tolerant, as informed by seed
industry) under well-watered conditions at two stages: milky grain stage and at crop maturity/harvesting stage.
Tolerant genotypes had significantly higher culm strength mean values over susceptible genotypes (Milky grain
stage: susceptible with 277 kPa, tolerant with 390 kPa; Harvesting stage: susceptible with 341 kPa, tolerant with
523 kPa). Again during summer season of 2019, 8 hybrids (2 susceptible and 6 tolerant) screened under wellwatered
conditions validated that tolerant genotypes had significantly higher average value of culm strength
(269 kPa) in comparison to susceptible ones (185 kPa). Based on these findings, 19 hybrids including one
susceptible check (Bayer 9444), 5 tolerant checks and 13 pipeline hybrids from eight seed companies were
evaluated during rainy season of 2019, which luckily got exposed to high winds with rains, showed that hybrids
having higher culm strength at crop maturity had higher levels of lodging tolerance in field conditions (and were having comparable culm strength to tolerant checks). Finally, based on four year multi-season and multienvironment
investigations, culm strength: a weather-independent, cost effective and easily scorable trait was
identified to help screen for lodging tolerance in pearl millet
 
Date 2020-02
 
Type Conference or Workshop Item
PeerReviewed
 
Format application/pdf
 
Language en
 
Identifier http://oar.icrisat.org/11687/1/Proceeding%20cover%20page%20%2B%20Culm%20Strength%20Key%20Trait%20to%20Identify%20Lodging%20Tolerant%20Genotypes%20in%20Pearl%20Millet.pdf
Gupta, S K and Shaikh, C G and Ponnaiah, G and Kalleshappa, C C and Kholova, J and Jayalekha, A K and Verma, Y S (2020) Culm Strength: Key Trait to Identify Lodging Tolerant Genotypes in Pearl Millet. In: 16th ROME International Conference on Advances in Agricultural, Biological and Environmental Sciences (RAABE-20), Feb. 3-5, 2020, Rome, Italy.