Influence of source manipulation and nitrogen regimes on phenological, canopy and panicle traits of Sorghum
Year: 2026
Type: article
Abstract: Sorghum productivity during the reproductive phase depends strongly on the maintenance of an effective photosynthetic canopy and adequate nutrient availability. The present study evaluated the effects of source manipulation through graded leaf defoliation and nitrogen management on phenological development, canopy characteristics and panicle architecture of sorghum during 2023-24 and 2024-25. Five source-manipulation treatments and four nitrogen regimes were evaluated, with observations recorded for days to anthesis, days to maturity, number of leaves, leaf area, leaf area index (LAI), panicle length and panicle circumference. Days to anthesis remained largely unaffected by either defoliation or nitrogen treatment, reflecting the fact that source manipulation was imposed at anthesis. In contrast, increasing defoliation progressively shortened crop duration and reduced canopy development. The most severe defoliation treatment (F5) consistently produced the lowest number of leaves, leaf area and LAI, with the response evident at both 10 and 25 days after treatment. Nitrogen application produced an opposite response, with the higher split nitrogen regime (N4) maintaining greater canopy development and delaying maturity. Panicle architecture followed a similar pattern, with increasing defoliation reducing panicle length and circumference, whereas higher nitrogen supply generally enhanced both traits. The contrasting responses of the intact-canopy and severe-source-limitation treatments were consistent across the two growing seasons. Overall, the findings demonstrate that maintenance of the upper photosynthetic canopy after anthesis, together with appropriately timed nitrogen management, is important for sustaining crop duration, canopy development and panicle architecture in sorghum.
Institution: Indira Gandhi Agricultural University
Language: English
Subfield: Agronomy and Crop Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: bronze
OpenAlex ID: W7203690657