Seed Number and 100-Seed Weight of Pearl Millet (Pennisetum glaucum L.) Respond Differently to Low Soil Moisture in Genotypes Contrasting for Drought Tolerance uri icon

abstract

  • Water stress after flowering, one of the major factors limiting yields of pearl millet,affects both seed setting and grain filling and is a consequence of more/lesswater used prior to anthesis. However, whether genotypes have different sensitivitiesfor seed setting and filling under drought, if exposed to similar stress intensity,is unclear. Experiments were conducted in two pairs of pearl milletgenotypes, that is, PRLT2/89-33 and H77/833-2, 863B and 841B, contrasting forterminal drought tolerance, and two genotypes, ICMR 01046 and ICMR 01029(IL-QTLs), introgressed with a terminal drought tolerance QTL from PRLT2/89-33 into H77/833-2. Total seed weight, panicle number, 100-seed weight, seednumber and stover biomass were measured at different soil moistures andthroughout grain filling. Sensitive H77/833-2 had higher seed number and yieldunder well-watered (WW) conditions than in PRLT2/89-33 and IL-QTLs. Uponincreases in water stress intensity, H77/833-2 suffered losses mostly in stover biomass(45 %) and seed number (60 %) at 0.3 FTSW whereas the biomass and seednumber of PRLT2/89-33 decreased little (20 % and 25 %). The 100-seed weightof H77/833-2 decreased only 20 % under stress. Tolerant 863B also maintained ahigher seed number and biomass under water stress than 841B. Grain fillingduration in PRLT2/89-33 and IL-QTLs was similar to that of H77/833-2 underWW conditions but lasted longer than in H77833-2 under water stress (WS).Similarly, seed growth of 863B was longer than 841B under WS. It is concludedthat the higher seed yield of tolerant parents PRLT2/89-33 and 863B, and of ILQTLsunder WS was explained by the retention of a higher number of seeds thanin sensitive lines, while the decrease in the 100-seed weight was proportionallyless than the decrease in seed number. Phenotype with lesser number and largersize of panicles and larger grain size, like genotypes PRLT2/89-33 and 863B, withstoodpost-anthesis water stress better. IL-QTL inherited part of these characteristics,indicating a role for the terminal drought QTL in maintaining larger seednumber and higher 100-seed weight. The continuous stover biomass increaseunder WW in H77/833-2, due to tillering, might indicate that tiller growth andgrains are in competition for resources after anthesis, and this may relate to therelatively shorter grain-filling period

publication date

  • 2014
  • 2014