Iron-deficiency chlorosis: Its heritability and effects on agronomic traits in a sorghum population

Abstract

Abstract One hundred S1, families from a random‐mating sorghum [Sorghum bicolor (L.) Moench] population (NP21R) were grown 2 years on a mixed, mesic Aridic Argiustoll (calcareous) soil that induced severe iron (Fe)‐deficiency chlorosis. Agronomic traits (flowering, plant,height, grain yield ha‐1, grain yield plant‐1, grain yield head‐1, seeds plant‐1, seeds head‐1, 100‐seed weight, and grain protein) were evaluated for S1 families over two replications of a split‐plot design with (+Fe) and without (‐Fe) iron supplied to plants in a foliar spray. Chlorosis ratings were recorded every other day for 37 days beginning 21 days after planting only in whole plots with the ‐Fe treatment. Broad‐sense heritability estimated from family plot data over 2 years for the average chlorosis rating was 0.86 ± 0.15. Agronomic traits improved consistently for plants receiving foliar Fe, but treatment means were significantly different for grain yield ha‐1 and grain yield plant”; only. Regression of the percentage decrease in the,‐Fe over the +Fe treatment means indicated that grain yield ha‐1 decreased more for S1 families in the ‐Fe treatment relative to the +Fe treatment per unit increase in the average chlorosis rating (21%) than did other traits.