Agriculture Reference
In-Depth Information
2013) resulting in drying up of inflorescences giving charred appearance.
Extended cold periods of 2012-2013 fruiting season as indicated
(Fig.
5.11
),
have besides adversely impacting the flowering phenology across
varieties including delayed flowering (late February-early March, 2013),
may possibly also render fruit growth and development stages vulnerable
to eventually increased hot and dry environmental cues, with adverse im-
pacts on later stages of fruit development especially, maturity (during June
to July). All these factors cumulatively may reduce the quantity and qual-
ity of fruit harvests in 2012-2013 fruiting season.
5.2.1.5
NUBBIN FRUIT FORMATION
'Dashehari'
cultivar, being highly sensitive to temperature fluxes in re-
spect of key reproductive phenophases viz., flowering and fruit set, also
gets highly impacted by the abnormal weather conditions especially, the
spatio-temporal relationships between T
max
and T
Tmin
. The clustering (nub-
bin) of fruit lets phenomenon may be due to prevalence of high fluctua-
tions in temperatures during February and March especially, the T
Tmin
of
cold winters which coincided with the period of flowering and fruit de-
velopment during 2013 fruiting season probably impacted by hormonal
interpolations; this type of weather extremism despite good intensity of
flowering and set, often ends up in clustering of fruit lets at the distal end
of the inflorescence where, higher percentage of perfect flowers normally
occurred in the panicle configuration. Such fruits invariably with aborted
embryos (
see the inset picture
) prematurely drop off and are not carried to
maturity, a direct loss to total crop outputs (Fig. 5.11).
Hormonal relationships also explained that, the normal fruits contained
higher concentrations of gibberellins and cytokinins and lower concentra-
tions of auxins and abscissic acid as compared to the nubbin fruits. These
findings perhaps explained the reasons of occurrence nubbin fruits that
have a slower growth rate than the seeded one and small in size, major-
ity of these fruits dropped and failed to reach full size (Shaban and Ibra-
him, 2009). Variety differences, effects of cold winter temperatures in this
regard though have been implicated; exact reasons for this phenomenon
however are not clearly understood (Campbell and Campbell, 1991).
